F5 Inter VLAN routing / forwarding

[root@ve10:Active] config  b virtual bar80 list
virtual bar80 {
   pool foo
   destination 172.28.19.252:80
   ip protocol 6
   profiles {
      http {}
      tcp {}
   }
}
[root@ve10:Active] config  b pool foo list
pool foo {
   members 200.200.200.101:80 {}
}

 on bigip, no routing is configured

[root@ve10:Active] config  b route list
No Routing Table Entries were found.

 on client (172.28.20.11), you can see although no routing is configured on bigip, bigip is able to send return traffic back to client properly. this is done by using auto last hop feature.

client  curl -I http://172.28.19.252
HTTP/1.1 200 OK
Date: Fri, 04 Jan 2013 17:32:38 GMT
Server: Apache/2.2.3 (CentOS)
Last-Modified: Sat, 27 Oct 2012 03:22:35 GMT
ETag: "4183f3-59-f28f94c0"
Accept-Ranges: bytes
Content-Length: 89
Content-Type: text/html; charset=UTF-8

 tcpdump on bigip

line (1) - (4) is on client-side (between client and bigip). line (5) - (8) is on server-side (between bigip and server).

this solution might be helpful to understand how tcp is set up.

sol8082: Overview of TCP connection set-up for BIG-IP LTM virtual server types
http://support.f5.com/kb/en-us/solutions/public/8000/000/sol8082.html

[root@ve10:Active] config  tcpdump -nni 0.0 port 80
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on 0.0, link-type EN10MB (Ethernet), capture size 108 bytes
(1) 01:08:06.556968 IP 172.28.20.11.44684 > 172.28.19.252.80: S 2710000848:2710000848(0) win 14600 
(2) 01:08:06.557007 IP 172.28.19.252.80 > 172.28.20.11.44684: S 3779632336:3779632336(0) ack 2710000849 win 4380 
(3) 01:08:06.559934 IP 172.28.20.11.44684 > 172.28.19.252.80: . ack 1 win 115 
(4) 01:08:06.559976 IP 172.28.20.11.44684 > 172.28.19.252.80: P 1:157(156) ack 1 win 115 
(5) 01:08:06.560015 IP 172.28.20.11.44684 > 200.200.200.101.80: S 3998985522:3998985522(0) win 4380 
(6) 01:08:06.560998 IP 200.200.200.101.80 > 172.28.20.11.44684: S 1193331176:1193331176(0) ack 3998985523 win 5792 
(7) 01:08:06.561015 IP 172.28.20.11.44684 > 200.200.200.101.80: . ack 1 win 4380 
(8) 01:08:06.561026 IP 172.28.20.11.44684 > 200.200.200.101.80: P 1:157(156) ack 1 win 4380