Postrouting TTL changes - does this work?

RouterOS General
1

Experimenting with postrouting mangle rules a number of ways.

Ping 1.1.1.1 say (note TTL return values). 48/49 usually the return value from 64 on one link.

Now if I reset the TTL on outgoing by changing the value up by 100 (64 seems to be the default on my mac and Mikrotik ping) i’d expect roughly a TTL return of what it was before + 100 ±.

It makes no difference as far as I can see.

If I reduce it to low values (below the TTL needed to get to 1.1.1.1) it times out or says TTL exceeded (depends on client) so works in some respect but anything above 12 roughly just returns as a residual TTL of 49.

Am I completely missing the point here?

/ip firewall mangle
add action=change-ttl chain=postrouting new-ttl=set:164 out-interface=lte1 passthrough=yes

2

Just wiresharked this. My misunderstanding.

Packets, sent to my own machine not the LTE interface are adhering to TTL shaping.

Return packet values of the TTL of the target machine (ICMP here) are what i’m seeing minus return path decrementing.