Talk:Internet sharing

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Latest comment: 24 July 2022 by Regid in topic How do I port forward?

The first method is nice for larger networks, it is explained in these articles: Simple stateful firewall HOWTO and NAT'ing firewall - Share your broadband connection 09:01, 25 October 2006 (PDT)Gilneas

I managed to do this with a straight through cable. --Factory 23:22, 10 August 2008 (EDT)

Chanches are that one of your Network Interface Cards is a Gigabit Ethernet Card which supports AUTO MDI-X according to its specification. AUTO MDI-X automagically adjusts to the cable type, so that it makes no difference which type you use to connect. The article is correct mentioning the use of a crossed cable. --Rondal 08:19, 24 August 2008 (EDT)

It's probably worth mentioning that eth0 and eth1 IPs on PC1 shold be in different ranges. I myself had a problem with routing when they were set up to (by default) and (according to the article). --phoederr 19:55, 12 January 2009

Connections suddenly timing out

I've been using this method for some time and noticed that sometimes a connection to a remote server stalls and times out for no apparent reason. It happens only with some particular servers. Just as if the server suddenly stopped sending data - even though everything works OK when connecting from the matchine with firewall (pc1). It turns out that some servers are misconfigured to report that they support PMTU discovery while in fact they ignore ICMP messages telling them that the packets are too large. You can find more information here:

The following iptables rule seems to be a good workaround:

iptables -A FORWARD -p tcp -m tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu

I did't want to add it to the article myself because I'm not sure if it is the best way to do this and if it does not have any undesirable side effects. It would be nice if someone could verify this and add it if it's OK. Cameel 00:09, 28 December 2010 (EST)


It's mentioned that systemd-networkd doesn't honor IP forwarding settings and to check out the bug report on how to manage it "until it is fixed". It actually it isn't a bug, so it won't be fixed (see IPForward on the manpage for The behavior will continue to remain. Should this be reworded / expanded / refer to the systemd-networkd page (which also might need to explain this a little)? Rdeckard (talk) 01:26, 3 May 2015 (UTC)Reply[reply]

If it is not a bug, then why is the bug still open? The man page doesn't say that this won't be fixed either. -- Lahwaacz (talk) 06:50, 3 May 2015 (UTC)Reply[reply]

How do I port forward?

Can someone update the documentation so I know how to port forward? -- Erkexzcx (talk) 13:38, 11 April 2019 (UTC)Reply[reply]

As in Nftables#NAT with port forwarding? Regid (talk) 16:40, 24 July 2022 (UTC)Reply[reply]