Forum Discussion

vbhugra's avatar
vbhugra
Icon for Nimbostratus rankNimbostratus
Nov 10, 2023

SNAT and Next hop based on Node address

I have a requirement wherein I have 2-nodes in a pool; of which 1 node is directly connected to F5 and the other one is behind a layer-3 router. I want to make an iRule if the directly connected nod...
devops
vbhugra's avatar
vbhugra
Icon for Nimbostratus rankNimbostratus

Hello Paulius,

The reason for not having a static route is we have clients coming from different interfaces.

The second thing is we do not have HTTP traffic coming to this VIP.  we have TCP traffic (SQL).

What else we can have other than HTTP_REQUEST?

when CLIENT_ACCEPTED priority 500 {

set DEFAULT_POOL [LB::server pool]

}

when <> priority 500 {

if { [active_members [LB::server pool]] == 0} {
snatpool SNAT_REP
pool DBS5G_REP_REMOTE
nexthop /DBS/DBS_CLIENT_174 10.219.30.65
} else {
pool ${DBS5G_REP_LOCAL}
}

}

Paulius's avatar
Paulius
Icon for MVP rankMVP
Nov 15, 2023

vbhugra The following iRule should work for the SQL communication.

when CLIENT_ACCEPTED priority 500 {

    set DEFAULT_POOL [LB::server pool]

    if { [active_members [LB::server pool]] == 0} {
        snatpool SNAT-<VS_IP>
        pool POOL-ServerBehindRouter
    } else {
        pool ${DEFAULT_POOL}
    }

}

I do not see why you cannot have the permanent route in place even if traffic is coming from different interfaces because the way the F5 reaches it will always be the same direction.