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From: Pablo Neira Ayuso <pablo@netfilter.org>
To: Frank Wunderlich <frank-w@public-files.de>
Cc: netfilter@vger.kernel.org
Subject: Re: Re: Flowtable with ppp/bridge
Date: Mon, 3 May 2021 00:11:22 +0200	[thread overview]
Message-ID: <20210502221122.GA19395@salvia> (raw)
In-Reply-To: <trinity-ff6011a6-3075-4189-8283-8dab8158b881-1619963468385@3c-app-gmx-bs63>

On Sun, May 02, 2021 at 03:51:08PM +0200, Frank Wunderlich wrote:
> Hi,
> 
> i got a bit further and it looks like an MTU-Issue
> 
> i tested now with my 5.10 bridges,vlan and pppoe
> 
> first 2 working without problems, pppoe works only if i reduce mtu to e.g. 1480 (pppoe has 1492).
>
> i tried with this patch (found as difference between my 5.10 and 5.12 hnat trees), but this does not solve it.
> 
> https://github.com/frank-w/BPI-R2-4.14/commit/5f7d57280c1982d993d5f4ff0edac310f820f607 (bpf: Drop MTU check when doing TC-BPF redirect to ingress)
> 
> any idea? i wonder why mtu is a problem here, as with 1500 default i
> still got internet-connection (over pppoe on main-router too) and
> due to Pathdiscovery it should fragment. Seems this is not working
> in 5.10 for flowtable. Without flowtable (disable "flow add" line,
> disabling "flags offload" is not enough) i have no issues.
> 
> any idea?

You have to add a rule to clamp TCP mss to path MTU.

... tcp flags syn tcp option maxseg size set rt mtu

  reply	other threads:[~2021-05-02 22:11 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-26 15:30 Flowtable with ppp/bridge Frank Wunderlich
2021-04-26 17:29 ` Pablo Neira Ayuso
2021-04-26 17:51   ` Frank Wunderlich
2021-04-26 17:57     ` Pablo Neira Ayuso
2021-04-26 18:08       ` Frank Wunderlich
2021-04-27 23:49         ` Pablo Neira Ayuso
2021-04-28  8:07           ` Frank Wunderlich
2021-04-28 17:26             ` Frank Wunderlich
2021-04-29 13:59               ` Aw: " Frank Wunderlich
2021-05-02 13:51                 ` Frank Wunderlich
2021-05-02 22:11                   ` Pablo Neira Ayuso [this message]
2021-05-03 18:56                     ` Aw: " Frank Wunderlich
2021-05-03 21:32                       ` Pablo Neira Ayuso
2021-05-04 10:54                         ` Aw: " Frank Wunderlich
2021-05-04 11:42                           ` Pablo Neira Ayuso
2021-05-05  8:55                             ` Aw: " Frank Wunderlich
2021-05-05 22:55                               ` Pablo Neira Ayuso
2021-05-06  9:53                                 ` Aw: " Frank Wunderlich
2021-05-06 15:51                                   ` Pablo Neira Ayuso
2021-05-10  6:50                                     ` Aw: " Frank Wunderlich
2021-05-10  8:24                                       ` Pablo Neira Ayuso
2021-05-10  9:00                                         ` Aw: " Frank Wunderlich

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