From: Florian Westphal <fw@strlen.de>
To: G H <uothrawn@yahoo.com>
Cc: "netfilter@vger.kernel.org" <netfilter@vger.kernel.org>
Subject: Re: Rewrite arp response with nft
Date: Sat, 20 Apr 2024 19:31:18 +0200 [thread overview]
Message-ID: <20240420173118.GA21662@breakpoint.cc> (raw)
In-Reply-To: <48471547.724608.1713545266678@mail.yahoo.com>
G H <uothrawn@yahoo.com> wrote:
> On early versions of Linux, I could use ebtables to rewrite the ARP packet using the below command. This ensures that the switch would only see MAC address 00:50:56:96:12:5e, not aa:18:f0:55:79:1e.
>
> ebtables -t nat -I POSTROUTING --logical-out br0 --src aa:18:f0:55:79:1e \
> -j snat --to-src 00:50:56:96:12:5e --snat-arp --snat-target ACCEPT
>
> I can get close to recreating this with nftables, but it is missing the functionality provided by the --snat-arp argument.
>
> table bridge filter {
> chain POSTROUTING {
> type filter hook postrouting priority 0; policy accept;
> ether saddr aa:18:f0:55:79:1e ether saddr set 00:50:56:96:12:5e
> }
> }
>
> My outgoing ARP packet has its source MAC address rewritten successfully, but the "is-at" still points to the original MAC address. How do I alter the outbound ARP response to set "is-at" to point to 00:50:56:96:12:5e?
No idea, but you might want to look at the "arp" payload expression.
Maybe:
arp operation reply arp daddr ether set ...
prev parent reply other threads:[~2024-04-20 17:31 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <48471547.724608.1713545266678.ref@mail.yahoo.com>
2024-04-19 16:47 ` Rewrite arp response with nft G H
2024-04-20 17:31 ` Florian Westphal [this message]
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