Does mailx send mail using an SMTP relay or does it directly connect to the target SMTP server?

Posted by iamrohitbanga on Super User See other posts from Super User or by iamrohitbanga
Published on 2010-05-04T13:17:09Z Indexed on 2010/05/04 13:19 UTC
Read the original article Hit count: 372

Filed under:

linux

|

mailx

|

smtp

|

nat

Suppose i send a mail using the following the following command:

mailx [email protected]

then does mailx first try to find out the SMTP server of my ISP for relaying the mail or does it connect directly. Does it depend on whether my PC has a public IP address or it is behind a NAT. How do I check the settings of mailx on my PC? How can I verify this using tcpdump?

© Super User or respective owner

Related posts about linux

apt-get install and update fail

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I've got a problem with apt-get update and apt-get install ... commands . every time update or installing fails and errors are : Get:1 http://dl.google.com stable Release.gpg [198B] Ign http://dl.google.com/linux/chrome/deb/ stable/main Translation-en_US Get:2 http://dl… >>> More
kernel module compiling error

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
sh@ubuntu:/home/ccpp/helloworld$ make gcc-4.6 -O2 -DMODULE -D_KERNEL_ -W -Wall -Wstrict-prototypes -Wmissing-prototypes -isystem /lib/modules/`uname -r`/build/include -c -o hello-1.o hello-1.c hello-1.c:4:0: warning: "MODULE" redefined [enabled by default] <command-line>:0:0: note: this is… >>> More
Build-Essentials installation failing

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I am having trouble accessing the several critical header files that show to be a part of the build process. The "Ubuntu Software Center" shows "Build Essentials" as installed: Next I did the following two commands, which did not improve the problem: ~$ sudo apt-get install build-essential [sudo]… >>> More
Updating Debian kernel

as seen on Super User - Search for 'Super User'
I'm trying to update my Debian machine to 2.6.32-46 (which is the new stable). However, after doing apt-get update my apt-cache search linux-image shows me: linux-headers-2.6.32-5-486 - Header files for Linux 2.6.32-5-486 linux-headers-2.6.32-5-686-bigmem - Header files for Linux 2.6.32-5-686-bigmem linux-headers-2… >>> More
Serial connection over a single USB cable (Windows to linux, or linux to linux)

as seen on Server Fault - Search for 'Server Fault'
I'm helping out with a project for an embedded device that only has USB and no serial. This device is running Linux. These days, when we need to connect to a serial port on a device we typically use a USB to serial adapter (on something like a phone system or a load balancing device, etc). I would… >>> More

Related posts about mailx

Which mailx package should I install for Nagios?

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I'm following the Nagios Ubuntu quickstart instructions. I'm on Ubuntu 10.10 and installing Nagios 3.2.3. At the bottom of the docs it says I need to install the mailx and postfix packages. (Postfix is already installed.) But when I try to install mailx, I get asked which of 3 packages to install: $… >>> More
Need to set mailx variable to specify the From address

as seen on Super User - Search for 'Super User'
Running Oracle Linux 5.8 (which is just re-branded RedHat EL 5.8) I must change the From address. But we have scripts that use mailx which cannot be re-written to use any extra flags, so I'd like to use internal variables instead, which I see on the linux.die.net manpage on mailx is an alternative… >>> More
Trying to send email attachment on HP UX using mailx through Perl isnt working

as seen on Stack Overflow - Search for 'Stack Overflow'
Here's my code that is not working: print "To: "; my $to=<>; chomp $to; print "From: "; my $from=<>; chomp $from; print "Attach: "; my $attach=<>; chomp $attach; print "Subject: "; my $subject=<>; chomp $subject; print "Message: "; my $message=<>; chomp $message; my… >>> More
setting mailx default smtp relay

as seen on Stack Overflow - Search for 'Stack Overflow'
I heave searched Google for this and cannot seem to find a soloution I have bsd-mailx on my server and it sends mail just fine However I wished to have a development environment at home. I need mailx such that php can use its mail function. However the mail is failing to resolve the domain name… >>> More
how to set the font with mailx?

as seen on Server Fault - Search for 'Server Fault'
Solaris Korn Shell I am writing sql reports to an oracle database, spooling them to a file and emailing them with mailx. I use the syntax below. The reports do not format properly, unless I use the Courier New font. How do I set this with mailx? mailx -s "MY REPORT, date +'%D %r " -r "REPORTING… >>> More