nanog mailing list archives
Re: What do you consider acceptable packet / session modification for a network operator?
From: Marco Moock via NANOG <nanog () lists nanog org>
Date: Fri, 26 Dec 2025 17:05:44 +0100
Am 26.12.2025 um 10:52:48 Uhr schrieb Tom Beecher:
Packet comes in with DF set. Egress interface MTU is too small. ICMP Frag Needed generated, source address is RFC1918 loopback from the router control plane. On the return trip, packet crosses network that (correctly) drops all RFC1918 sourced traffic.
Can't you use NAT (the Cisco ISR devices support nat inside on lo too IIRC) or configure the source address for outgoing router traffic?
This is not a routing problem at all. This is very common.
Indeed, but a filtering problem if routers on the path filter non-public address ranges. -- Gruß Marco Send unsolicited bulk mail to 1766742768muell () cartoonies org
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Current thread:
- Re: What do you consider acceptable packet / session modification for a network operator?, (continued)
- Re: What do you consider acceptable packet / session modification for a network operator? William Herrin via NANOG (Dec 26)
- Re: What do you consider acceptable packet / session modification for a network operator? Marco Moock via NANOG (Dec 26)
- Re: What do you consider acceptable packet / session modification for a network operator? Saku Ytti via NANOG (Dec 26)
- Re: What do you consider acceptable packet / session modification for a network operator? Marco Moock via NANOG (Dec 26)
- Re: What do you consider acceptable packet / session modification for a network operator? Saku Ytti via NANOG (Dec 27)
- Re: What do you consider acceptable packet / session modification for a network operator? William Herrin via NANOG (Dec 27)
- Re: What do you consider acceptable packet / session modification for a network operator? nanog--- via NANOG (Dec 30)
- Re: What do you consider acceptable packet / session modification for a network operator? William Herrin via NANOG (Dec 30)
- Re: What do you consider acceptable packet / session modification for a network operator? Lukas Tribus via NANOG (Dec 30)
- Re: What do you consider acceptable packet / session modification for a network operator? Tom Beecher via NANOG (Dec 26)
- Re: What do you consider acceptable packet / session modification for a network operator? Marco Moock via NANOG (Dec 26)
- Re: What do you consider acceptable packet / session modification for a network operator? Jared Mauch via NANOG (Dec 26)
- Re: What do you consider acceptable packet / session modification for a network operator? Ca By via NANOG (Dec 25)