tcp delays in jails

[Ivan Voras]

William Taylor wrote:
> I recently started having a problem with tcp connections in one of my jails.
> Im running 4.9-stable

I guess it will not do any good to tell you to upgrade to 8.0? :)

> both sendmail and perdition experience the same problem. I even tried stopping
> everything on the box and the problem still persists.

Just to verify - the problem is on the side of the servers (TCP listeners)?

> Connections to other jails on different ip's on the same box are fine.
> There seems to be about a 5 second delay.
> 
> From this snippet of a ktrace I did you can see what looks to be a delay of about 5 seconds  after the CALL kevent

I'm not sure what you are tracing but this trace looks like something 
having to do with DNS.

Does DNS resolve properly on the box? Reverse DNS also? Some servers, 
ssh and probably sendmail also, do a reverse DNS lookup on the 
connecting client.

> 86872 perdition 1259617190.144575 GIO   fd 6 wrote 43 bytes
>        "n\M^]\^A\0\0\^A\0\0\0\0\0\0\^B18\^B96\^B81\^C206\ain-addr\^Darpa\0\0\f\0\^A"
>  86872 perdition 1259617190.144584 RET   sendto 43/0x2b
>  86872 perdition 1259617190.144592 CALL  gettimeofday(0xbfbfde9c,0)
>  86872 perdition 1259617190.144604 RET   gettimeofday 0
>  86872 perdition 1259617190.144619 CALL  kevent(0x4,0xbfbfdec0,0x1,0xbfbfdec0,0x1,0xbfbfdea4)
>  86872 perdition 1259617195.147032 RET   kevent 0
>  86872 perdition 1259617195.147085 CALL  close(0x6)
>  86872 perdition 1259617195.147120 RET   close 0
>  86872 perdition 1259617195.147138 CALL  socket(0x2,0x2,0)
>  86872 perdition 1259617195.147150 RET   socket 6
>  86872 perdition 1259617195.147159 CALL  sendto(0x6,0xbfbfe100,0x2b,0,0x28269b60,0x10)
>  86872 perdition 1259617195.147186 GIO   fd 6 wrote 43 bytes
> 
> 
> Any ideas of what I can do to figure this out?

Just the generic ones... try seeing if DNS and reverse DNS work first.