From: Frank Wunderlich <frank-w@public-files.de>
To: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: netfilter@vger.kernel.org
Subject: Aw: Re: Re: Re: Re: Flowtable with ppp/bridge
Date: Wed, 5 May 2021 10:55:24 +0200 [thread overview]
Message-ID: <trinity-95c69486-d51d-4c21-8923-e845e0c04269-1620204924394@3c-app-gmx-bs20> (raw)
In-Reply-To: <20210504114256.GA6473@salvia>
Hi,
> Gesendet: Dienstag, 04. Mai 2021 um 13:42 Uhr
> Von: "Pablo Neira Ayuso" <pablo@netfilter.org>
> You also need TCP clamp MTU in a non-flowtable setup.
hi,
thats clear now, but i guess i had not much problems till now because of Path discovery
> > $ifwan is my ppp8, and "tcp flags syn" imho should match syn and syn+ack.
>
> syn+ack matches iifname $ifwan.
imho this depends on the initiator of the connection. if i try to establish connection from my lan, this is true, and mss is set by oifname ppp0. Afair SYN-ACK from "Server" does use my size for syn-ack (if it is smaller that its size), or am i wrong?
if i initiate a connection from the public internet, i need to match iifname ppp0, but only if my ISP does not modify mss on pushing the initial SYN-Packet through the ppp-tunnel. But afair in this case i modify mss with oifname, but on response (SYN-ACK) i send back to the initiator.
> Only the two initial syn and syn+ack packets follow the classic
> forwarding path. Therefore, the FORWARD chain in your example above is
> evaluated only for the two initial packets of the TCP connection.
>
> You should add the 'flow add' rule at the bottom of your ruleset in
> your example above.
good to know, so flowtable does always "accept" matching packets (here all udp/tcp), right?
and final foward-policy does neyer hit if flowtable condition matches.
regards Frank
next prev parent reply other threads:[~2021-05-05 8:55 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
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 ` Frank Wunderlich [this message]
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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