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Feature Request: Multicast ping. Change TTL in Echo-reply from VyOS
Open, Requires assessmentPublic

Description

Set TTL = 255 (or 64) In reply to multicast ping (useful for multicast troubleshooting)
VyOS now puts TTL = 1 in response to such requests.
Tested in VyOS 1.4-rolling-202110310317
tcpdump:

10.27.27.2 > 224.5.5.5: ICMP echo request, id 16523, seq 5, length 64
17:17:03.182502 IP (tos 0x0, ttl 64, id 13692, offset 0, flags [none], proto ICMP (1), length 84)
10.27.27.7 > 10.27.27.2: ICMP echo reply, id 16523, seq 5, length 64
17:17:03.537059 IP (tos 0xc0, ttl 1, id 0, offset 0, flags [DF], proto IGMP (2), length 52, options (RA))

224.5.5.5 - MC group
10.27.27.2 - MC source
10.27.27.7 - MC receiver

Details

Difficulty level
Unknown (require assessment)
Version
VyOS 1.4-rolling-202110310317
Why the issue appeared?
Will be filled on close
Is it a breaking change?
Unspecified (possibly destroys the router)
Issue type
Unspecified (please specify)

Event Timeline

@NikolayP Can you play with it?

iptables -t mangle -A OUTPUT -d 10.27.27.2 -j TTL --ttl-set 64

Or any other suggestions?