Maintained by: NLnet Labs

[Unbound-users] TCP random timeouts

Thomas Guthmann
Mon Nov 15 01:35:20 CET 2010


Hey guys,

I am encountering some TCP issues on a RHEL5.5 with unbound 1.4.6 
(homemade), ldns 1.6.4 (EPEL5) and libevent-1.4.13 (stock:).

TCP stops working after a random amount of time (after a day or two). As 
a result we have timeouts or sometimes an answer after many seconds. To 
fix this odd behaviour I must restart unbound. I can see interesting 
stuff in the logs which doesn't sound good :

[..]
2010-11-14T20:58:50.266456+11:00 ns2 unbound: [11863:0] error: tcp 
writev: Broken pipe
2010-11-14T21:01:32.850306+11:00 ns2 unbound: [11863:0] error: tcp 
writev: Broken pipe
2010-11-14T21:02:40.550057+11:00 ns2 unbound: [11863:0] error: tcp 
writev: Broken pipe
2010-11-14T21:04:39.722422+11:00 ns2 unbound: [11863:0] error: tcp 
writev: Broken pipe
2010-11-14T21:09:22.810925+11:00 ns2 unbound: [11863:0] error: tcp 
writev: Broken pipe
2010-11-14T21:12:07.241707+11:00 ns2 unbound: [11863:0] error: tcp 
writev: Broken pipe
2010-11-14T21:32:12.354364+11:00 ns2 unbound: [11863:0] error: tcp 
writev: Broken pipe
2010-11-14T21:38:47.172330+11:00 ns2 unbound: [11863:0] error: tcp 
writev: Broken pipe
2010-11-14T21:38:47.785624+11:00 ns2 unbound: [11863:0] error: tcp 
writev: Broken pipe
2010-11-14T21:38:47.791953+11:00 ns2 unbound: [11863:0] error: tcp 
writev: Broken pipe
2010-11-14T21:38:47.792277+11:00 ns2 unbound: [11863:0] error: tcp 
writev: Broken pipe
2010-11-14T21:38:50.490228+11:00 ns2 unbound: [11863:0] error: tcp 
writev: Broken pipe
2010-11-14T21:38:50.490766+11:00 ns2 unbound: [11863:0] error: tcp 
writev: Broken pipe
2010-11-14T21:42:49.785485+11:00 ns2 unbound: [11863:0] error: tcp 
writev: Broken pipe
2010-11-14T21:42:49.808128+11:00 ns2 unbound: [11863:0] error: tcp 
writev: Broken pipe
2010-11-14T21:45:01.650444+11:00 ns2 unbound: [11863:0] error: tcp 
writev: Broken pipe
2010-11-14T22:28:38.252697+11:00 ns2 unbound: [11863:0] error: tcp 
writev: Broken pipe
2010-11-14T22:41:44.186902+11:00 ns2 unbound: [11863:0] error: tcp 
writev: Broken pipe


Note that I am using : interface-automatic: yes.

How I compile/package unbound :

%configure  --with-ldns= --with-libevent --with-pthreads --with-ssl \
             --disable-rpath --enable-debug --disable-static \
             --with-conf-file=%{_sysconfdir}/%{name}/unbound.conf \
             --with-pidfile=%{_localstatedir}/run/%{name}/%{name}.pid \

Could this be linked to the fact I compiled Unbound 1.4.6 with ldns 
1.6.4 (saying that because Paul Wouters opened a thread about possible 
dangerous linking when building RPM - something you've just fixed in 1.4.7).

Any thoughts ? Except this small issue unbound is quite awesome. Many 
thanks for this great piece of software.

Thomas