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> Residential: Your TP Link […] is probably already blocking icmp for you. If it does, it generally won't pass telco CPE certification, i.e. Comcast and the l
by eqvinox 1y ago
> Residential: Your TP Link […] is probably already blocking icmp for you.
If it does, it generally won't pass telco CPE certification, i.e. Comcast and the likes won't be selling it to you in any bundle. Blocking ICMP Fragmentation Needed / ICMPv6 Packet Too Big is a hard fail on all of those, other message types can vary.
(Source: I work in this area.)
[Ed.: to be clear, there is no single "telco CPE certification"; each telco decides this on their own. A bunch of them form groups/"alliances" though, and a lot of the certification requirements are the same everywhere.]
- protocolture 1y agoInbound echo request and echo reply are almost always blocked in my experience.
- eqvinox 1y agoWhich is ≈mostly≈ fine; I'm just saying people in appropriate places (deciding which CPEs get sold to you) have gotten rather touchy about the PMTU bits. And rightfully so!
- protocolture 1y agoAbsolutely. I supported a mid size WISP for 2 years and something like 60% of the issues they sent my way were ultimately resolved with MSS Adjust or MTU clamping.