possible ttl bug in linux version of mgen

[PatrickTague]

i'm trying to use mgen for traffic profiling in the CORE emulator. however, for every TCP flow i try to create, it sets the TTL field to 3, regardless of what parameter i provide as part of the flow definition. is there an easy way to fix this?

for context, i'm using the version of mgen that is installed via apt in ubuntu, i believe it's 5.02c.

[bebopagogo]

I think this has been addressed in the more recent source code that is on GitHub. The intent was to have the _default_ TTL for _multicast_ to be 3 but at one point that also got mistakenly applied to unicast too.

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On Oct 3, 2021, at 6:41 PM, PatrickTague ***@***.***> wrote:  i'm trying to use mgen for traffic profiling in the CORE emulator. however, for every TCP flow i try to create, it sets the TTL field to 3, regardless of what parameter i provide as part of the flow definition. is there an easy way to fix this? for context, i'm using the version of mgen that is installed via apt in ubuntu, i believe it's 5.02c. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub, or unsubscribe. Triage notifications on the go with GitHub Mobile for iOS or Android.

[PatrickTague]

thank you for the weekend reply! is there any way to change it to not be 3? i'm unable to establish any longer connections, regardless of what configuration i try.

[bebopagogo]

Have you tried setting the global/default TTL on the command-line before any ON or LISTEN command? For example:

mgen ttl 255 event "on 1 tcp dst 127.0.0.1/5002 per [10 1024]"

I tested this with a 5.02 build, observed the TTL=3 as you have (even with the TTL as part of the on event specification), but the above command line produced packets with TTL=255

[bebopagogo]

(I also tested this with the current MGEN 5..1.1 source code from GitHub and it uses TTL=255 for unicast flows.)

[PatrickTague]

ooh, that worked. thank you! i was hoping to not need ~70 students in my class install from source if at all possible, so that will do it!