I have a problem with a FreeBSD server. There is a FreeBSD 9.0 amd64, two network cards em1 (internet), em0 (local network) configured firewall ipfw, natd, squid (not transparent), the server acts as a gateway for access to the Internet. Next problem: upload via squid is very low. At this moment I see next: natd, dhcpd load the cpu at that time when uploading through squid and there are a lot of traffic through the loopback interface. ipfw show output 0100 655389684 36707144666 allow ip from any to any via lo0 00200 0 0 deny ip from any to 127.0.0.0/8 00300 0 0 deny ip from 127.0.0.0/8 to any 00400 0 0 deny ip from any to ::1 00500 0 0 deny ip from ::1 to any 00600 4 292 allow ipv6-icmp from :: to ff02::/16 00700 0 0 allow ipv6-icmp from fe80::/10 to fe80::/10 00800 1 76 allow ipv6-icmp from fe80::/10 to ff02::/16 00900 0 0 allow ipv6-icmp from any to any ip6 icmp6types 1 01000 0 0 allow ipv6-icmp from any to any ip6 icmp6types 2,135,136 01100 1615 76160 deny ip from 192.168.1.1 to any in via em1 01200 0 0 deny ip from 199.69.99.11 to any in via em0 01300 46652 3705426 deny ip from any to 172.16.0.0/12 via em1 01400 3936404 345618870 deny ip from any to 192.168.0.0/16 via em1 01500 4 336 deny ip from any to 0.0.0.0/8 via em1 01600 4129 387621 deny ip from any to 169.254.0.0/16 via em1 01700 0 0 deny ip from any to 192.0.2.0/24 via em1 01800 917566 33777571 deny ip from any to 224.0.0.0/4 via em1 01900 147872 22029252 deny ip from any to 240.0.0.0/4 via em1 02000 1132194739 1190981955947 divert 8668 ip4 from any to any via em1 02100 3 248 deny ip from 172.16.0.0/12 to any via em1 02200 35925 2281289 deny ip from 192.168.0.0/16 to any via em1 02300 1808 122494 deny ip from 0.0.0.0/8 to any via em1 02400 3 174 deny ip from 169.254.0.0/16 to any via em1 02500 0 0 deny ip from 192.0.2.0/24 to any via em1 02600 0 0 deny ip from 224.0.0.0/4 to any via em1 02700 0 0 deny ip from 240.0.0.0/4 to any via em1 02800 960156249 1095316736582 allow tcp from any to any established 02900 64236062 8243196577 allow ip from any to any frag 03000 34 1756 allow tcp from any to me dst-port 25 setup 03100 193 11580 allow tcp from any to me dst-port 53 setup 03200 63 4222 allow udp from any to me dst-port 53 03300 64 8350 allow udp from me 53 to any 03400 417 24140 allow tcp from any to me dst-port 80 setup 03500 211 10472 allow ip from any to me dst-port 3389 setup 05300 77 4488 allow ip from any to me dst-port 1723 setup 05400 3 156 allow ip from any to me dst-port 8443 setup 05500 9882 590596 allow tcp from any to me dst-port 22 setup 05600 1 60 allow ip from any to me dst-port 2000 setup 05700 0 0 allow ip from any to me dst-port 2201 setup 07400 4241779 216690096 deny log logamount 1000 ip4 from any to any in via em1 setup proto tcp 07500 21135656 1048824936 allow tcp from any to any setup 07600 474447 35298081 allow udp from me to any dst-port 53 keep-state 07700 532 40612 allow udp from me to any dst-port 123 keep-state 65535 1990638432 1122305322718 allow ip from any to any systat -ifstat when uploading via squid Load Average ||| Interface Traffic Peak Total tun0 in 79.507 KB/s 232.479 KB/s 42.314 GB out 2.022 MB/s 2.424 MB/s 59.662 GB lo0 in 4.450 MB/s 4.450 MB/s 43.723 GB out 4.450 MB/s 4.450 MB/s 43.723 GB em1 in 2.629 MB/s 2.982 MB/s 464.533 GB out 2.493 MB/s 2.875 MB/s 484.673 GB em0 in 240.458 KB/s 296.941 KB/s 442.368 GB out 512.508 KB/s 850.857 KB/s 416.122 GB top output PID USERNAME THR PRI NICE SIZE RES STATE C TIME WCPU COMMAND 66885 root 1 92 0 26672K 2784K CPU3 3 528:43 65.48% natd 9160 dhcpd 1 45 0 31032K 9280K CPU1 1 7:40 32.96% dhcpd 66455 root 1 20 0 18344K 2856K select 1 119:27 1.37% openvpn 16043 squid 1 20 0 44404K 17884K kqread 2 0:22 0.29% squid squid.conf cat /usr/local/etc/squid/squid.conf # # Recommended minimum configuration: # acl manager proto cache_object acl localhost src 127.0.0.1/32 ::1 acl to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1 # Example rule allowing access from your local networks. # Adapt to list your (internal) IP networks from where browsing # should be allowed acl localnet src 10.0.0.0/8 # RFC1918 possible internal network acl localnet src 172.16.0.0/12 # RFC1918 possible internal network acl localnet src 192.168.0.0/16 # RFC1918 possible internal network acl localnet src fc00::/7 # RFC 4193 local private network range acl localnet src fe80::/10 # RFC 4291 link-local (directly plugged) machines acl SSL_ports port 443 acl Safe_ports port 80 # http acl Safe_ports port 21 # ftp acl Safe_ports port 443 # https acl Safe_ports port 70 # gopher acl Safe_ports port 210 # wais acl Safe_ports port 1025-65535 # unregistered ports acl Safe_ports port 280 # http-mgmt acl Safe_ports port 488 # gss-http acl Safe_ports port 591 # filemaker acl Safe_ports port 777 # multiling http acl CONNECT method CONNECT # # Recommended minimum Access Permission configuration: # # Only allow cachemgr access from localhost http_access allow manager localhost http_access deny manager # Deny requests to certain unsafe ports http_access deny !Safe_ports # Deny CONNECT to other than secure SSL ports http_access deny CONNECT !SSL_ports # We strongly recommend the following be uncommented to protect innocent # web applications running on the proxy server who think the only # one who can access services on "localhost" is a local user http_access deny to_localhost # # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS # # Example rule allowing access from your local networks. # Adapt localnet in the ACL section to list your (internal) IP networks # from where browsing should be allowed http_access allow localnet http_access allow localhost # And finally deny all other access to this proxy http_access deny all # Squid normally listens to port 3128 http_port 192.168.1.1:3128 # Uncomment and adjust the following to add a disk cache directory. #cache_dir ufs /var/squid/cache 100 16 256 # Leave coredumps in the first cache dir coredump_dir /var/squid/cache I understand that the traffic passes through the SQUID several times. But can not find why.