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  • Should I expect ICMP transit traffic to show up when using debug ip packet with a mask on a Cisco IOS router?

    - by David Bullock
    So I am trying to trace an ICMP conversation between 192.168.100.230/32 an EZVPN interface (Virtual-Access 3) and 192.168.100.20 on BVI4. # sh ip access-lists 199 10 permit icmp 192.168.100.0 0.0.0.255 host 192.168.100.20 20 permit icmp host 192.168.100.20 192.168.100.0 0.0.0.255 # sh debug Generic IP: IP packet debugging is on for access list 199 # sh ip route | incl 192.168.100 192.168.100.0/24 is variably subnetted, 2 subnets, 2 masks C 192.168.100.0/24 is directly connected, BVI4 S 192.168.100.230/32 [1/0] via x.x.x.x, Virtual-Access3 # sh log | inc Buff Buffer logging: level debugging, 2145 messages logged, xml disabled, Log Buffer (16384 bytes): OK, so from my EZVPN client with IP address 192.168.100.230, I ping 192.168.100.20. I know the packet reaches the router across the VPN tunnel, because: policy exists on zp vpn-to-in Zone-pair: vpn-to-in Service-policy inspect : acl-based-policy Class-map: desired-traffic (match-all) Match: access-group name my-acl Inspect Number of Half-open Sessions = 1 Half-open Sessions Session 84DB9D60 (192.168.100.230:8)=>(192.168.100.20:0) icmp SIS_OPENING Created 00:00:05, Last heard 00:00:00 ECHO request Bytes sent (initiator:responder) [64:0] Class-map: class-default (match-any) Match: any Drop 176 packets, 12961 bytes But I get no debug log, and the debugging ACL hasn't matched: # sh log | inc IP: # # sh ip access-lists 198 Extended IP access list 198 10 permit icmp 192.168.100.0 0.0.0.255 host 192.168.100.20 20 permit icmp host 192.168.100.20 192.168.100.0 0.0.0.255 Am I going crazy, or should I not expect to see this debug log? Thanks!

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  • using gmail as email relay for sendmail

    - by Nikita
    I used to be able to send emails using a gmail account & sendmail configured using one of the guides on the Internet, for example: http://appgirl.net/blog/configuring-sendmail-to-relay-through-gmail-smtp/ This is a small server and I've recently moved it to a different house. And sendmail has stop working. The only thing different in the network setup is a new router. What is happening: In the log files, I see the following error: ...stat=Deferred: smtp.gmail.com: No route to host When I run from the command line: strace sendmail -f A -t B -u "Subject" -m "Message" -tls=yes ssl=yes -s smtp.gmail.com:587 -xu A -xp XYZ It hangs on this call: recvfrom(3, "m0\201\203\0\1\0\0\0\0\0\0\4ares\3lan\0\0\34\0\1", 8192, 0, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("192.168.1.254")}, [16]) = 26 close(3) = 0 time(NULL) = 1339997943 open("/etc/localtime", O_RDONLY) = 3 fstat64(3, {st_mode=S_IFREG|0644, st_size=3477, ...}) = 0 fstat64(3, {st_mode=S_IFREG|0644, st_size=3477, ...}) = 0 mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb76ff000 read(3, "TZif2\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\4\0\0\0\4\0\0\0\0"..., 4096) = 3477 _llseek(3, -24, [3453], SEEK_CUR) = 0 read(3, "\nEST5EDT,M3.2.0,M11.1.0\n", 4096) = 24 close(3) = 0 munmap(0xb76ff000, 4096) = 0 socket(PF_FILE, SOCK_DGRAM|SOCK_CLOEXEC, 0) = 3 connect(3, {sa_family=AF_FILE, path="/dev/log"}, 110) = 0 send(3, "<18>Jun 18 01:39:03 sendmail[268"..., 96, MSG_NOSIGNAL) = 96 nanosleep({60, 0}, So it looks like at some point it tries to resolve the DNS name, but I don't have anything running on 53, so it dies out and then just hangs. The other interesting thing is that msmtp works just fine on the same server. Update: ares in strace output is actually the name of my server, but .254 IP address is the address of the router. Could anyone tell me why this is happening or what further steps can I take to investigate the issue? Thanks!

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  • Selling Federal Enterprise Architecture (EA)

    - by TedMcLaughlan
    Selling Federal Enterprise Architecture A taxonomy of subject areas, from which to develop a prioritized marketing and communications plan to evangelize EA activities within and among US Federal Government organizations and constituents. Any and all feedback is appreciated, particularly in developing and extending this discussion as a tool for use – more information and details are also available. "Selling" the discipline of Enterprise Architecture (EA) in the Federal Government (particularly in non-DoD agencies) is difficult, notwithstanding the general availability and use of the Federal Enterprise Architecture Framework (FEAF) for some time now, and the relatively mature use of the reference models in the OMB Capital Planning and Investment (CPIC) cycles. EA in the Federal Government also tends to be a very esoteric and hard to decipher conversation – early apologies to those who agree to continue reading this somewhat lengthy article. Alignment to the FEAF and OMB compliance mandates is long underway across the Federal Departments and Agencies (and visible via tools like PortfolioStat and ITDashboard.gov – but there is still a gap between the top-down compliance directives and enablement programs, and the bottom-up awareness and effective use of EA for either IT investment management or actual mission effectiveness. "EA isn't getting deep enough penetration into programs, components, sub-agencies, etc.", verified a panelist at the most recent EA Government Conference in DC. Newer guidance from OMB may be especially difficult to handle, where bottom-up input can't be accurately aligned, analyzed and reported via standardized EA discipline at the Agency level – for example in addressing the new (for FY13) Exhibit 53D "Agency IT Reductions and Reinvestments" and the information required for "Cloud Computing Alternatives Evaluation" (supporting the new Exhibit 53C, "Agency Cloud Computing Portfolio"). Therefore, EA must be "sold" directly to the communities that matter, from a coordinated, proactive messaging perspective that takes BOTH the Program-level value drivers AND the broader Agency mission and IT maturity context into consideration. Selling EA means persuading others to take additional time and possibly assign additional resources, for a mix of direct and indirect benefits – many of which aren't likely to be realized in the short-term. This means there's probably little current, allocated budget to work with; ergo the challenge of trying to sell an "unfunded mandate". Also, the concept of "Enterprise" in large Departments like Homeland Security tends to cross all kinds of organizational boundaries – as Richard Spires recently indicated by commenting that "...organizational boundaries still trump functional similarities. Most people understand what we're trying to do internally, and at a high level they get it. The problem, of course, is when you get down to them and their system and the fact that you're going to be touching them...there's always that fear factor," Spires said. It is quite clear to the Federal IT Investment community that for EA to meet its objective, understandable, relevant value must be measured and reported using a repeatable method – as described by GAO's recent report "Enterprise Architecture Value Needs To Be Measured and Reported". What's not clear is the method or guidance to sell this value. In fact, the current GAO "Framework for Assessing and Improving Enterprise Architecture Management (Version 2.0)", a.k.a. the "EAMMF", does not include words like "sell", "persuade", "market", etc., except in reference ("within Core Element 19: Organization business owner and CXO representatives are actively engaged in architecture development") to a brief section in the CIO Council's 2001 "Practical Guide to Federal Enterprise Architecture", entitled "3.3.1. Develop an EA Marketing Strategy and Communications Plan." Furthermore, Core Element 19 of the EAMMF is advised to be applied in "Stage 3: Developing Initial EA Versions". This kind of EA sales campaign truly should start much earlier in the maturity progress, i.e. in Stages 0 or 1. So, what are the understandable, relevant benefits (or value) to sell, that can find an agreeable, participatory audience, and can pave the way towards success of a longer-term, funded set of EA mechanisms that can be methodically measured and reported? Pragmatic benefits from a useful EA that can help overcome the fear of change? And how should they be sold? Following is a brief taxonomy (it's a taxonomy, to help organize SME support) of benefit-related subjects that might make the most sense, in creating the messages and organizing an initial "engagement plan" for evangelizing EA "from within". An EA "Sales Taxonomy" of sorts. We're not boiling the ocean here; the subjects that are included are ones that currently appear to be urgently relevant to the current Federal IT Investment landscape. Note that successful dialogue in these topics is directly usable as input or guidance for actually developing early-stage, "Fit-for-Purpose" (a DoDAF term) Enterprise Architecture artifacts, as prescribed by common methods found in most EA methodologies, including FEAF, TOGAF, DoDAF and our own Oracle Enterprise Architecture Framework (OEAF). The taxonomy below is organized by (1) Target Community, (2) Benefit or Value, and (3) EA Program Facet - as in: "Let's talk to (1: Community Member) about how and why (3: EA Facet) the EA program can help with (2: Benefit/Value)". Once the initial discussion targets and subjects are approved (that can be measured and reported), a "marketing and communications plan" can be created. A working example follows the Taxonomy. Enterprise Architecture Sales Taxonomy Draft, Summary Version 1. Community 1.1. Budgeted Programs or Portfolios Communities of Purpose (CoPR) 1.1.1. Program/System Owners (Senior Execs) Creating or Executing Acquisition Plans 1.1.2. Program/System Owners Facing Strategic Change 1.1.2.1. Mandated 1.1.2.2. Expected/Anticipated 1.1.3. Program Managers - Creating Employee Performance Plans 1.1.4. CO/COTRs – Creating Contractor Performance Plans, or evaluating Value Engineering Change Proposals (VECP) 1.2. Governance & Communications Communities of Practice (CoP) 1.2.1. Policy Owners 1.2.1.1. OCFO 1.2.1.1.1. Budget/Procurement Office 1.2.1.1.2. Strategic Planning 1.2.1.2. OCIO 1.2.1.2.1. IT Management 1.2.1.2.2. IT Operations 1.2.1.2.3. Information Assurance (Cyber Security) 1.2.1.2.4. IT Innovation 1.2.1.3. Information-Sharing/ Process Collaboration (i.e. policies and procedures regarding Partners, Agreements) 1.2.2. Governing IT Council/SME Peers (i.e. an "Architects Council") 1.2.2.1. Enterprise Architects (assumes others exist; also assumes EA participants aren't buried solely within the CIO shop) 1.2.2.2. Domain, Enclave, Segment Architects – i.e. the right affinity group for a "shared services" EA structure (per the EAMMF), which may be classified as Federated, Segmented, Service-Oriented, or Extended 1.2.2.3. External Oversight/Constraints 1.2.2.3.1. GAO/OIG & Legal 1.2.2.3.2. Industry Standards 1.2.2.3.3. Official public notification, response 1.2.3. Mission Constituents Participant & Analyst Community of Interest (CoI) 1.2.3.1. Mission Operators/Users 1.2.3.2. Public Constituents 1.2.3.3. Industry Advisory Groups, Stakeholders 1.2.3.4. Media 2. Benefit/Value (Note the actual benefits may not be discretely attributable to EA alone; EA is a very collaborative, cross-cutting discipline.) 2.1. Program Costs – EA enables sound decisions regarding... 2.1.1. Cost Avoidance – a TCO theme 2.1.2. Sequencing – alignment of capability delivery 2.1.3. Budget Instability – a Federal reality 2.2. Investment Capital – EA illuminates new investment resources via... 2.2.1. Value Engineering – contractor-driven cost savings on existing budgets, direct or collateral 2.2.2. Reuse – reuse of investments between programs can result in savings, chargeback models; avoiding duplication 2.2.3. License Refactoring – IT license & support models may not reflect actual or intended usage 2.3. Contextual Knowledge – EA enables informed decisions by revealing... 2.3.1. Common Operating Picture (COP) – i.e. cross-program impacts and synergy, relative to context 2.3.2. Expertise & Skill – who truly should be involved in architectural decisions, both business and IT 2.3.3. Influence – the impact of politics and relationships can be examined 2.3.4. Disruptive Technologies – new technologies may reduce costs or mitigate risk in unanticipated ways 2.3.5. What-If Scenarios – can become much more refined, current, verifiable; basis for Target Architectures 2.4. Mission Performance – EA enables beneficial decision results regarding... 2.4.1. IT Performance and Optimization – towards 100% effective, available resource utilization 2.4.2. IT Stability – towards 100%, real-time uptime 2.4.3. Agility – responding to rapid changes in mission 2.4.4. Outcomes –measures of mission success, KPIs – vs. only "Outputs" 2.4.5. Constraints – appropriate response to constraints 2.4.6. Personnel Performance – better line-of-sight through performance plans to mission outcome 2.5. Mission Risk Mitigation – EA mitigates decision risks in terms of... 2.5.1. Compliance – all the right boxes are checked 2.5.2. Dependencies –cross-agency, segment, government 2.5.3. Transparency – risks, impact and resource utilization are illuminated quickly, comprehensively 2.5.4. Threats and Vulnerabilities – current, realistic awareness and profiles 2.5.5. Consequences – realization of risk can be mapped as a series of consequences, from earlier decisions or new decisions required for current issues 2.5.5.1. Unanticipated – illuminating signals of future or non-symmetric risk; helping to "future-proof" 2.5.5.2. Anticipated – discovering the level of impact that matters 3. EA Program Facet (What parts of the EA can and should be communicated, using business or mission terms?) 3.1. Architecture Models – the visual tools to be created and used 3.1.1. Operating Architecture – the Business Operating Model/Architecture elements of the EA truly drive all other elements, plus expose communication channels 3.1.2. Use Of – how can the EA models be used, and how are they populated, from a reasonable, pragmatic yet compliant perspective? What are the core/minimal models required? What's the relationship of these models, with existing system models? 3.1.3. Scope – what level of granularity within the models, and what level of abstraction across the models, is likely to be most effective and useful? 3.2. Traceability – the maturity, status, completeness of the tools 3.2.1. Status – what in fact is the degree of maturity across the integrated EA model and other relevant governance models, and who may already be benefiting from it? 3.2.2. Visibility – how does the EA visibly and effectively prove IT investment performance goals are being reached, with positive mission outcome? 3.3. Governance – what's the interaction, participation method; how are the tools used? 3.3.1. Contributions – how is the EA program informed, accept submissions, collect data? Who are the experts? 3.3.2. Review – how is the EA validated, against what criteria?  Taxonomy Usage Example:   1. To speak with: a. ...a particular set of System Owners Facing Strategic Change, via mandate (like the "Cloud First" mandate); about... b. ...how the EA program's visible and easily accessible Infrastructure Reference Model (i.e. "IRM" or "TRM"), if updated more completely with current system data, can... c. ...help shed light on ways to mitigate risks and avoid future costs associated with NOT leveraging potentially-available shared services across the enterprise... 2. ....the following Marketing & Communications (Sales) Plan can be constructed: a. Create an easy-to-read "Consequence Model" that illustrates how adoption of a cloud capability (like elastic operational storage) can enable rapid and durable compliance with the mandate – using EA traceability. Traceability might be from the IRM to the ARM (that identifies reusable services invoking the elastic storage), and then to the PRM with performance measures (such as % utilization of purchased storage allocation) included in the OMB Exhibits; and b. Schedule a meeting with the Program Owners, timed during their Acquisition Strategy meetings in response to the mandate, to use the "Consequence Model" for advising them to organize a rapid and relevant RFI solicitation for this cloud capability (regarding alternatives for sourcing elastic operational storage); and c. Schedule a series of short "Discovery" meetings with the system architecture leads (as agreed by the Program Owners), to further populate/validate the "As-Is" models and frame the "To Be" models (via scenarios), to better inform the RFI, obtain the best feedback from the vendor community, and provide potential value for and avoid impact to all other programs and systems. --end example -- Note that communications with the intended audience should take a page out of the standard "Search Engine Optimization" (SEO) playbook, using keywords and phrases relating to "value" and "outcome" vs. "compliance" and "output". Searches in email boxes, internal and external search engines for phrases like "cost avoidance strategies", "mission performance metrics" and "innovation funding" should yield messages and content from the EA team. This targeted, informed, practical sales approach should result in additional buy-in and participation, additional EA information contribution and model validation, development of more SMEs and quick "proof points" (with real-life testing) to bolster the case for EA. The proof point here is a successful, timely procurement that satisfies not only the external mandate and external oversight review, but also meets internal EA compliance/conformance goals and therefore is more transparently useful across the community. In short, if sold effectively, the EA will perform and be recognized. EA won’t therefore be used only for compliance, but also (according to a validated, stated purpose) to directly influence decisions and outcomes. The opinions, views and analysis expressed in this document are those of the author and do not necessarily reflect the views of Oracle.

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  • Connecting to same public IP from different locations yields different results

    - by DHall
    Since yesterday I've been unable to access one of my favorite time-wasting sites, boston.com. It starts to load but then it gets redirected to pagesinxt or something like that. After some investigation, I've narrowed it down to an issue with cache.boston.com, but only from my work location. I found the IP (216.38.160.107) , but even that doesn't work correctly from here at work. When I do a telnet 216.38.160.107 80 GET http://cache.boston.com/universal/css/hp_bgcom.css from another location, I get a nice long CSS, as expected. From here, I get an error (trimmed for size): HTTP/1.1 400 Bad Request Your request could not be processed. Request could not be handled This could be caused by a misconfiguration, or possibly a malformed request. For assistance, contact your network support team. Is there any way I can troubleshoot this further on my end? Tracert doesn't tell me anything too useful: Tracing route to vwrpx1.ttn.xpc-mii.net [216.38.160.107] over a maximum of 30 hops: 1 * * * Request timed out. Since it's not really work-related, I don't really want to bring it up to our network team unless I know what's going on, or if there's some risk to the network (ex. malware or something)

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  • mysqldump skip one table

    - by danneth
    I'm running a cronjob to backup our system using mysqldump. The database contains 90 or so tables. One of these tables is HUGE and every once in a while causes the dump to fail. From the manual I see that you can specify specific tables to dump shell> mysqldump [options] db_name [tbl_name ...] This got me thinking. What if I have two jobs, one for dumping the huge table, and one for all the others. To accomplish this it would be nice if I could to something like shell> mysqldump -u backupuser -p database huge_table > db_huge_table.sql shell> mysqldump -u backupuser -p database --skip huge_table > db_rest.sql Unfortenately I'm not seeing such and option. I could of course explicitly state the 90 tables, but that just seems like a mess. Another option would be a script of some sort, but before checking that route I'll try this resource. MySQL is 5.1.61 on CentOS 6.2

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  • IP6 seems to be enabled - How do I configure it without interfering with IP4?

    - by Mister IT Guru
    I noticed that some of my Centos boxes have IP6 enabled, and seem to have addresses. I have no problem with this, but I would like to get a handle on it, and even connect to them using IP6. This would really help if for any reason DHCP has a hiccup. But I'm a bit lost as to where the configuration on my CentOS box is. (I am also on google researching this, but I like server fault! :) ) I am hoping that I would be able to log into this via the VPN because every now and then that DHCP device has a bad morning, and needs to be restarted. (I'm also looking into this issue, but someone else handles that, management separation gone mad!) It's a remote client, so it would be a lot easier for me to connect to these systems which seem to self configure, to use that as a pivot via ssh tunnels to get to other remote devices to continue to manage them, while out main route is fixed. I guess, my questions are How can I configure IP6 without interfering with IP4, and On CentOS, can I influence this auto configuration I seem to be seeing?

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  • XP box with 3 NICs on Server 2003 Domain

    - by Hannibal
    I have assigned all three NICs IP addresses that are outside the DHCP pool. I have 2 NICs are connected to 1 switch and the 3rd to my second switch. I want to assign one of the two NICs on the 1st switch to "normal" network activity (e.g. internet access, RDP, etc.) The other two NICs I want to reserve for mirroring ports on their respective switches. While this machine is connected to the domain I can access the internet and Remote Desktop. I have no idea which NIC I am using until I start mirroring a port, at which time, if I happen to be connected through one of the NICs I have dedicated to mirroring, I lose my remote desktop. I am aware that I would have more control over the NICs using Linux. I want to explore Windows solutions before I go that route because reinstalling another OS would be inconvenient (but not impossible). I would likely use a version of Backtrack (3 or 4 not sure). I would also have to learn how to access the machine remotely but I've done it before so this would be a minor obstacle. Thank you for your assistance.

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  • AJP Connector Apache-Tomcat with php and java application

    - by Safari
    I have a question about proxy and ajp module. On my machine I have a Apache web server and a Tomcat servlet container. On Tomcat is running a my java webapplication. On Apache I have some services and I can call these in this way: http://myhos/service1 http://myhos/service2 http://myhos/service3 I would configurate a ajp connector to call my tomcat webapplication from Apache. I would somethin as http://myhost to call the Tomcat webapp. So, I configurated my apache in this way..and I have what I wanted: I can use http://myHost to visualize the Tomcat webApp by Apache. <VirtualHost *:80> ProxyRequests off ProxyPreserveHost On ServerAlias myserveralias ErrorLog logs/error.log CustomLog logs/access.log common <Proxy *> Order deny,allow Allow from all </Proxy> ProxyPass /server-status ! ProxyPass /balancer-manager ! ProxyPass / balancer://mycluster/ stickysession=JSESSIONID nofailover=Off maxattempts=1 <Proxy balancer://mycluster> BalancerMember ajp://myIp:8009 min=10 max=100 route=portale loadfactor=1 ProxySet lbmethod=bytraffic </Proxy> <Location /balancer-manager> SetHandler balancer-manager Order deny,allow Allow from localhost </Location> LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\"" combined LogFormat "%h %l %u %t \"%r\" %>s %b" common LogFormat "%{Referer}i -> %U" referer LogFormat "%{User-agent}i" agent </VirtualHost> But, now I can't use the apache services: If I use http://myhos/service1 I have an error because apache try to search service1 on my tomcatWebApp. Is there a way to fix it?

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  • Technology mash: is this possible?

    - by Jon Story
    I'm in the process of setting up my own DNS+hosting on a couple of VPS and my home machines, mostly for academic/learning purposes, but also for convenient accessing of my files, hosting my personal websites, private git repositories etc. I've got a main web server with DNS, and a slave DNS server. I've also got a couple of machines at home doing file hosting, video streaming and all that fun stuff. I'm intending to use my VPS's to provide myself with a dynamic DNS system so that I can point mydomain.com at my DNS servers, with home.mydomain.com going into my home network via a raspberry pi. HOWEVER.... I've not got access to the network infrastructure at home (rented accommodation with managed internet), so I can't forward the ports on the router to my own machines. As such, I'm wondering if it's possible to route all the traffic via an SSH/HTTP tunnel through one of the VPS? My plan is to have the raspberry pi provide a VPN into my home network. The raspberry pi uses SSH to connect to the VPS, and the VPS forwards any traffic to home.mydomain.com via the tunnel to the raspberry pi. Is this even possible, and how do I go about it? I don't mind getting my hands dirty with coding and low level tools, I'm just not sure where to start or what the best way to go about it is.

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  • Find slow network nodes between two data centers

    - by 2called-chaos
    I've got a problem with syncing big amount of data between two data centers. Both machines have got a gigabit connection and are not fully occupied but the fastest that I am able to get is something between 6 and 10 Mbit = not acceptable! Yesterday I made some traceroute which indicates huge load on a LEVEL3 router but the problem exists for weeks now and the high response time is gone (20ms instead of 300ms). How can I trace this to find the actual slow node? Thought about a traceroute with bigger packages but will this work? In addition this problem might not be related to one of our servers as there are much higher transmission rates to other servers or clients. Actually office = server is faster than server <= server! Any idea is appreciated ;) Update We actually use rsync over ssh to copy the files. As encryption tends to have more bottlenecks I tried a HTTP request but unfortunately it is just as slow. We have a SLA with one of the data centers. They said they already tried to change the routing because they say this is related to a cheap network where the traffic gets routed through. It is true that it will route through a "cheapnet" but only the other way around. Our direction goes through LEVEL3 and the other way goes through lambdanet (which they said is not a good network). If I got it right (I'm a network intermediate) they simulated a longer path to force routing through LEVEL3 and they announce LEVEL3 in the AS path. I basically want to know if they're right or they're just trying to abdicate their responsibility. The thing is that the problem exists in both directions (while different routes), so I think it is in the responsibility of our hoster. And honestly, I don't believe that there is a DC2DC connection which only can handle 600kb/s - 1,5 MB/s for weeks! The question is how to detect WHERE this bottleneck is

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  • Router vs switch in a LAN [closed]

    - by servernewbie
    If I have a LAN and and connect it with a switch, I understand it uses a CAM table to route packets in layer 2 (by saving mac to port relations). So far all good. However, when using a router for a LAN (ONLY for a LAN, not to connect it to "the outside" WAN/internet/etc) I get a bit confused as to how it internally processes packets. I would first split this into two router scenarios: Router with buit-in switch In this scenario, I would expect that it will act exactly as a switch with a CAM table internally. This would probably benefit a bit in speed (guessing here?) compared to the next option. Router without built-in switch Here is where I get confused. If hostA wants to send a packet to hostB, it will ARP to find hostB's MAC address and send it there. Now, if we had a switch (above scenario) this would be easy. But how does it work now in a router WITHOUT a switch? If I would guess, hostA would send an Ethernet frame with hostB's MAC address to the line. The router would fetch the packet (even though the router has another MAC address, it would still fetch this packet even if it only contains hostB's MAC address). It would strip the Ethernet frame header and check the IP, and then check its own internal ARP table again for the MAC address. Now, this would seem like a waste of resources compared to a router with a built-in switch. But maybe it does not work like that at all. Does it also contain a CAM table? If that would be true, what would then the difference between these two routers really be?

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  • Intermittently uncommunicative subnets

    - by mhd
    Last week proved me a veritable Cassandra: I've always said that it's a bad idea to have only one firewall/router, without a backup or failover. And thus our Cisco PIX went haywire, refusing to route properly. And of course, the only one available here on short notice is me, and while I'm quite grounded in Linux, I'm really a developer not a sysadmin (the fact that this hit me on sysadmin appreciation day is a bit ironic). Anyway, this weekend I tried to hack up a temporary solution: I used an old server with enough NICs (two built-in, four on a card) to serve as a gateway and firewall. Due to some problems with the raid controller, I got only two router distros running, and between Untangle and Ebox I decided for the latter. Now everything is quite okay. I've got all the different subnets we've got here (all with separate switches) talking to each other and even to the internet (Cisco 2800 router, T1 lines). But from time to time (20-60 minute intervals), I get a total routing failure. Our main, office subnet can't talk to our server subnet and can't connect to the internet. This is not the end of a gradual slowdown, either everything's working perfectly or I get a total lack of communication for about two minutes each time. Now I'm a bit at wits end what to check. At least with the default EBox setup, nothing in /var/log shows anything weird and it doesn't exactly have lots of built-in monitoring tools. So I'm hoping someone here could give me some pointers about what to look out for. I did change the ethernet cable from the office switch to the firewall, with no results. I might change switches, although within the switch it seems to work ok enough. Edit: I'm not sure whether this is the sole cause of the problem, but after I noticed a few DHCP entries just before the last drop of connectivity, I tried to reproduce that. And alas, whenever I renew a DHCP connection, I can't access other subnets anymore. Running ISC DHCPD 3.0.6.

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  • How to configure a large mtu (linux)

    - by Somejan
    I have a gigabit ethernet connection from my laptop to my router, and a working ipv6 connection to the internet. I can receive very large packets from sites on the internet, with sizes up to at least 10000 bytes (according to wireshark). (edit: turns out to be linux's 'generic receive offload') However, when trying to send anything, my local computer fragments at just below 1500 bytes for ipv6. (On ipv4, I can send tcp packets to the internet of at least 1514 bytes, I can ping with packets up to the configured mtu of 6128 but they are blackholed.) I'm on ubuntu 12.04. I have configured an mtu for my eth0 of 6128 (the maximum it accepts), both using ip link set dev eth0 mtu 6128 and in the NetworkManager applet gui, and restarted the connection. ip link show eth0 shows the 6128 mtu is indeed set. ip -6 route shows that none of the paths the kernel knows about have an mtu set. I can ping over ipv4 with packets up to 6128 bytes (though I don't get responses), but when I do ping6 myrouter -c3 -s1500 -Mdo I get error replies from my own computer saying that the packets are too large and the mtu is 1480. I have confirmed with Wireshark that nothing is put on the wire, and the replies are indeed generated by my own computer. So, how do I get my computer to use the larger mtu?

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  • How to install Windows 7 on a MacBook with HDDs and no optical drive, without rEFIt

    - by user1238528
    I just removed the SuperDrive on my MacBook Pro and replaced it with an SSD. So now my laptop has a SSD, and a HDD, but no optical drive. I have Lion on the SSD and I want to install Windows 7 on the HDD. Unfortunately, Boot Camp only will install Windows off of the Windows DVD. I have made a bootable Windows 7 thumb drive but my MacBook Pro won’t boot off it. So my question is how can I install Windows on the other HDD? I have thought about maybe using Oracle VirtualBox to install it on that hard drive, but I don’t know if that would allow me to boot directly into Windows. I really don't want to go down the whole virtualization route. I know I could just take out the SSD, put back in the optical drive, run the Windows 7 DVD, take the optical drive back out, put the SSD back in. But that sounds like a nightmare. Also, I really don’t want to use things like rEFIt. Any advice?

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  • One dns server in different subnets

    - by hofmeister
    I have installed a small Linux server; the server is in a different subnet as the internet hosts. I added a route to my nat router to create a connection between both subnets. In both subnets I use an extra dhcp Server. Subnet A: 192.168.0.0/26 Subnet B: 192.168.1.0/26 Router: 192.168.0.1, Server in A: 192.168.0.62, Server in B: 192.168.1.62 internet ____ nat router ___ (Sub A)___ internet hosts | |____(Sub B)___ other hosts I could ping every host. Also the hosts which are connected to the subnet b, has internet connection. But sadly I have a problem with the dns server. I use the dnsServer from my nat router, I set the dns Server for subnet b to the ip 192.168.0.1, but every dns entries are equal with the hostname from my linux server. Example if the hostname from the server is test Test 192.168.0.62 //Server subnet a Test-2 192.168.1.62 //Server subnet b Test-2-2 192.168.1.1 //host a Test-2-2-2 192.168.1.2 //host b Any idea what went wrong? The internet dns resolution works fine.

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  • Access server using IP on another interface

    - by Markos
    I am using Windows Server 2012 instead of a router for my home network. Currently I am using RRAS and computers from local network can access Internet correctly. Here is a map of the current setup: [PC1] ---| |---- (lan ip)[Server](wan ip)--> internet [PC2] ---| I have applications running on Server, such as IIS and others. All can be accessed from internet using wan ip and from lan using lan ip. I have a domain, lets say its my-domain.com, which is resolved to my wan ip. What I want is to enable my LAN computers to be able to connect to services on my server using the very same address as internet users: eg http://my-domain.com/. However this does not work for my lan computers. What I understand is that I need to set up some kind of loopback route in a way that packets comming to LAN interface get routed to WAN interface. But I haven't found how to achieve this (in fact, I don't know WHAT to search for). Feel free to ask for additional informations and I will try to update the question.

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  • Mangling traffic from a Mikrotik Router

    - by TiernanO
    I have a MikroTik powered Router in the house with a couple of internet connections (2 200/10Mb Cable modems and a 100/20Mb VDSL Line). I am using Mangle rules to set routing marks and NAT rules to do some load balancing, and everything seems to be going grand... But it only works for traffic from outside the router... Let me explain: I have 4 GigE ports on the machine, WAN1,2 and 3, and a LAN port named LAN1. All traffic from LAN1 is getting mangled (as it should be) but traffic from the load router itself (proxy traffic, IPv6 tunnels, VPN connections) are not being mangled. They get the first route to 0.0.0.0/0, which in my case is WAN2, and stick with it. So, how do I get traffic from the local router to be mangled? Originally it was proxy traffic that caused the problem, but now with IPv6 and VPN, they are more important to be mangled... last time i enabled IPv6 traffic, all traffic only went though WAN2, and the rest where unused... Any ideas?

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  • Can I boot up a virtual machine natively?

    - by Anshul
    My question is: Is is possible to run a virtual machine natively on your hardware if you have installed the proper drivers etc? In other words, can I use a VHD as a regular hard drive to boot from? The reason I want to do this is that I do both graphics-intensive and audio-intensive work, but my computer is not powerful enough to handle both at the same time and many times I install a bunch of audio programs that I don't want affecting the stability of my graphics programs. Basically I wanted to have sandboxing between the two sets of applications. So I tried running the graphics-intensive programs in a VirtualBox VM and the audio-intensive work natively (simply because it's a pain to route ASIO audio devices in/out of VirtualBox). This kind-of works - the graphics-intensive stuff is tolerable, but still relatively slow, because it's running inside a VM. So my next idea was to just dual-boot and install the graphics and audio programs in separate partitions but I frequently use them in tandem, so it wouldn't be practical to reboot my machine every time I need to use the other set of programs. But I could live with this scenario: If I need to do more audio-intensive stuff, I'll just boot up to the audio partition and run the graphics programs in a VM, and then when I'm working heavily on the graphics part, I'll just boot the graphics partition as a regular OS directly on the hardware. Is this possible? For example by booting up a VHD as a regular hard drive? Or by setting up dual-boot, and every time the audio partition is shut down, synchronize the graphics VM VHD with the native graphics partition? Is it practical, given the above scenario? And if it's not possible, barring buying another computer, can anyone suggest a best-of-all-worlds setup (the two worlds being performance, sandboxing, and running in parallel) for the above scenario? Thanks in advance.

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  • How to make an x.509 certificate from a PEM one?

    - by Ken
    I'm trying to test a script, locally, which involves uploading a file using a Java-based program to a FileZilla FTPES server. For the real thing, there is a real certificate on the FZ server, and the upload step (tested alone) seems to work fine. I've installed FileZilla Server on my dev box (so it'll test uploading from localhost to localhost). I don't have a real certificate for it, of course, so I used the "Generate new certificate..." button in FZ. It works fine from an interactive FTPES program (as long as I OK the unknown cert), but from my Java program it throws a javax.net.ssl.SSLHandshakeException ("unable to find valid certification path to requested target"). So how do I tell Java that this certificate is OK with me? (I know there's a way to change the Java program to accept any certificate, but I don't want to go down that route. I want to test it just as it will happen in production, and I don't want to ignore unknown certificates in production.) I found that Java has a program called "keytool" that seems to be for managing this sort of thing, but it complains that the certificate file that FZ generated is not an "x.509" file. A posting from the FZ side said it was "PEM encoded". I have "openssl" here, which looks like it's perfect for converting between certificate formats, but I think my understanding of certificate formats is wrong because I'm not seeing anything obvious. My knowledge of security certificates is a bit shaky, so if my title is stupidly wrong, please help by fixing that. :-)

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  • Cisco IOS ACL: Don't permit incoming connections just because they are from port 80

    - by cjavapro
    I am going much based on my memory and I may not be correct on all of this. On a Cisco 851 (IOS) that uses a BVI or a bridge-route (the servers on the inside are configured with static and public IP addresses). I would apply two access lists (both end with deny ip any any log) on FastEthernet4 (the WAN port). There would be one for FA4 in and another for FA4 out. FA4 out would have a line like access-list 110 permit 98.76.54.0 0.0.0.255 gt 1023 any eq http I think this means from 98.76.54.* with a from port of at least 1024 can connect to any other machine with a destination port 80. So, then I have to allow the response to the HTTP connection. FA4 in would have a line like access-list 120 permit any eq http 98.76.54.0 0.0.0.255 gt 1023 Now the problem with that is that anybody on the outside can set their from port to port 80 and then connect to any inside port that is at least 1024. How do we prevent this and require the incoming data to be a response to the outgoing data.

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  • Switch Before Firewall / Router - Multiple public IPs

    - by rii
    I currently Have a 10Mbit Full duplex circuit connected to a small unmanaged switch which then connects to a Sonicwall Firewall / Router. I have several public IP addresses (/28) that are assigned to several devices in my setup. Now the problem is the small switch I have was lent to me and needs to be returned, I have replaced this switch with several other switches but for some reason any other switch I use causes the network to become extremely slow. I believe this is a problem with the autonegotiation of theses hubs, so I am thinking of purchasing a small managed switch (cisco 300 series) and making the receiving port on the swith Explicitly 10Mbit Full Duplex and see if this works. My question is, being that this is a managed switch and needs an IP, will I still be able to run my public ips through it? Say the circuit has 70.80.4.1 - 7 will I still be able to assign 70.80.4.2 to my firewall and 70.80.4.3 to my router connected to some other port in the switch? Will I have to assign the switch a public IP address in this range as well for it to "route" to those other devices or does the switch does not care what IPs goes through it while operating as a Layer 2 Switch? Any help would be greatly appreciated. Thanks in advanced!

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  • What's the best way to telnet from a remote Windows PC without using RDP?

    - by Rob D.
    Three Networks: 10.1.1.0 - Mine 172.1.1.0 - My Branch Office 172.2.2.0 - My Branch Office's VOIP VLAN. My PC is on 10.1.1.0. I need to telnet into a Cisco router on 172.2.2.0. The 10.1.1.0 network has no routes to 172.2.2.0, but a VPN connects 10.1.1.0 to 172.1.1.0. Traffic on 172.1.1.0 can route to 172.2.2.0. All PCs on 172.1.1.0 are running Windows XP. Without disrupting anyone using those PCs, I want to open a telnet session from one of those PCs to the router on 172.2.2.0. I've tried the following: psexec.exe \\branchpc telnet 172.2.2.1 psexec.exe \\branchpc cmd.exe telnet 172.2.2.1 psexec.exe \\branchpc -c plink -telnet 172.2.2.1 Methods 1 and 2 both failed because telnet.exe is not usable over psexec. Method 3 actually succeeded in creating the connection, but I cannot login because the session registers my carriage return twice. My password is always blank because at the "Username:" prompt I'm effectively typing: Routeruser[ENTER][ENTER] It's probably time to deploy WinRM... Does anyone know of any other alternatives? Does anyone know how I can fix plink.exe so it only receives one carriage return when I use it over psexec?

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  • Vyatta masquerade out bridge interface

    - by miquella
    We have set up a Vyatta Core 6.1 gateway on our network with three interfaces: eth0 - 1.1.1.1 - public gateway/router IP (to public upstream router) eth1 - 2.2.2.1/24 - public subnet (connected to a second firewall 2.2.2.2) eth2 - 10.10.0.1/24 - private subnet Our ISP provided the 1.1.1.1 address for us to use as our gateway. The 2.2.2.1 address is so the other firewall (2.2.2.2) can communicate to this gateway which then routes the traffic out through the eth0 interface. Here is our current configuration: interfaces { bridge br100 { address 2.2.2.1/24 } ethernet eth0 { address 1.1.1.1/30 vif 100 { bridge-group { bridge br100 } } } ethernet eth1 { bridge-group { bridge br100 } } ethernet eth2 { address 10.10.0.1/24 } loopback lo { } } service { nat { rule 100 { outbound-interface eth0 source { address 10.10.0.1/24 } type masquerade } } } With this configuration, it routes everything, but the source address after masquerading is 1.1.1.1, which is correct, because that's the interface it's bound to. But because of some of our requirements here, we need it to source from the 2.2.2.1 address instead (what's the point of paying for a class C public subnet if the only address we can send from is our gateway!?). I've tried binding to br100 instead of eth0, but it doesn't seem to route anything if I do that. I imagine I'm just missing something simple. Any thoughts?

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  • Access server using IP on another interface

    - by Markos
    I am using Windows Server 2012 instead of a router for my home network. Currently I am using RRAS and computers from local network can access Internet correctly. Here is a map of the current setup: [PC1] ---| |---- (lan ip)[Server](wan ip)--> internet [PC2] ---| I have applications running on Server, such as IIS and others. All can be accessed from internet using wan ip and from lan using lan ip. I have a domain, lets say its my-domain.com, which is resolved to my wan ip. What I want is to enable my LAN computers to be able to connect to services on my server using the very same address as internet users: eg http://my-domain.com/. However this does not work for my lan computers. What I understand is that I need to set up some kind of loopback route in a way that packets comming to LAN interface get routed to WAN interface. But I haven't found how to achieve this (in fact, I don't know WHAT to search for). Feel free to ask for additional informations and I will try to update the question.

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  • How do I uninstall a ruby version installed via source?

    - by Aaron McIver
    I installed a version (1.9.3-p194) of ruby via source using make install and realized this may have been the wrong route to take. Upon doing this, I realized this was a mistake and I should be using a solution such as rvm to address my ruby versions within the OS. I looked to see if an uninstall existed to be ran in conjunction with make and it didn't. I then proceeded to install rvm and add the aforementioned version in to my list of managed rubies within rvm which is not listed as ext-ruby-1.9.3-p194. rvm rubies ext-ruby-1.9.3-p194 [ x86_64 ] =* ruby-1.9.3-p194 [ x86_64 ] # => - current # =* - current && default # * - default** When I perform an rvm remove, it simply removes it from the rubies list however it still exists within /usr/local/bin. I am not concerned with the system install ruby version residing in /usr/bin as I understand that is tied to the OS and should simply be ignored. How can I safely uninstall/remove the aforementioned version and all the places in which it was installed, short of looking at the install script?

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