From 816cbe8c7c77a01009f685d1c6d1e1dc9fd0bf7b Mon Sep 17 00:00:00 2001 From: Brian Somers Date: Sat, 4 Oct 1997 00:19:58 +0000 Subject: [PATCH] Mention a pre-2.2.5 bug in the tun driver that gets tickled by the "set mtu" command (now that we can see the IO error in the log file). --- FAQ/FAQ.sgml | 25 +++++++++++++++++++++++-- 1 file changed, 23 insertions(+), 2 deletions(-) diff --git a/FAQ/FAQ.sgml b/FAQ/FAQ.sgml index a00e5e21aa..1bbecc5689 100644 --- a/FAQ/FAQ.sgml +++ b/FAQ/FAQ.sgml @@ -1,12 +1,12 @@ - +
Frequently Asked Questions for FreeBSD 2.X <author>Maintainer: Peter da Silva <tt><htmlurl url='mailto:peter@taronga.com' name='<peter@taronga.com>'></tt> -<date>$Date: 1997-10-03 20:53:27 $</date> +<date>$Date: 1997-10-04 00:19:58 $</date> <abstract> This is the FAQ for FreeBSD systems version 2.X All entries are @@ -3548,6 +3548,27 @@ MYADDR: disable pred1 </verb> + <sect2> + <heading>Ppp locks up during file transfers with IO errors</heading> + + <p> + Under FreeBSD 2.2.2 and before, there was a bug in the tun + driver that prevents incoming packets of a size larger than + the tun interface's MTU size. Receipt of a packet greater than + the MTU size results in an IO error being logged via syslogd. + + <p> + The ppp specification says that an MRU of 1500 should + <bf>always</bf> be accepted as a minimum, despite any LCP + negotiations, therefore it is possible that should you decrease + the MTU to less than 1500, your ISP will transmit packets of + 1500 regardless, and you will tickle this non-feature - locking + up your link. + + <p> + The problem can be circumvented by never setting an MTU of + less than 1500 under FreeBSD 2.2.2 or before. + <sect2> <heading>None of this helps - I'm desperate !</heading>