these are tcpdump and stream content of 2nd syslog server (irule). hostname in message shows client hostname (ve1100). you know since it is in payload, it is not changed by address translation. 172.28.19.80 is f5 selfip. i am not aware of how to change source ip in the ip header.
so, would it be possible to configure your syslog server to use ip or hostname in syslog message instead of ip in ip header when correlation?
tcpdump:
192011-12-21 14:37:10.05834822.018464172.28.19.80192.168.206.42Syslog223LOCAL0.NOTICE: Dec 20 22:36:24 ve1100 notice tmsh[10730]: 01420002:5: AUDIT - pid=10730 user=root folder=/Common module=(tmos) status=[Command OK] cmd_data=list sys db ucs.loadtime one-line\n
stream content:
<133>Dec 20 22:36:24 ve1100 notice tmsh[10730]: 01420002:5: AUDIT - pid=10730 user=root folder=/Common module=(tmos) status=[Command OK] cmd_data=list sys db ucs.loadtime one-line