Local Loop : Setting interface MTU using DHCP

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{ 2009 10 19 }

Setting interface MTU using DHCP

DHCP can be used to set the interface MTU on end hosts using option 26. For example (with dnsmasq), to set the MTU of clients on the lan interface to 1400 bytes, use: dhcp-option=lan,26,1400

I’m using this to work around MTU issues caused by a tunnel. It seems to work well so far… no need for IP fragmentation or TCP MSS re-adjustment by a router.

The corresponding Debian /etc/network/interfaces magic for static iface stanzas is "mtu 1400",

Posted by Simeon Miteff on Monday, October 19, 2009, at 9:00 am. Filed under Technical. Tagged dhcp, fragmentation, MSS, MTU, tunnels. Follow any responses to this post with its comments RSS feed. You can post a comment or trackback from your blog.

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