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Maniphest T3973

Feature Request: Multicast ping. Change TTL in Echo-reply from VyOS
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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

Unknown Object (User) created this task.Nov 6 2021, 3:38 AM
Unknown Object (User) created this object in space S1 VyOS Public.
pasik subscribed.Nov 6 2021, 10:00 AM
Viacheslav subscribed.Nov 25 2021, 8:21 PM

@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?

n.fort subscribed.Jul 11 2023, 11:24 AM

Once we move to new firewall and re-work on mangle/PBR, this could be achieved easily.

Viacheslav assigned this task to n.fort.Jan 20 2024, 10:06 AM
Viacheslav triaged this task as Wishlist priority.
dmbaturin edited projects, added VyOS 1.5 Circinus; removed VyOS 1.4 Sagitta.Apr 12 2024, 3:11 PM
vyosbot removed n.fort as the assignee of this task.Jul 12 2024, 6:02 AM
dmbaturin added a project: Restricted Project.Mon, Sep 16, 4:16 PM