Re: [squid-users] What exactly is "Do not set REUSEADDR on port."

On Jan 19, 2008 8:22 PM, Andrew Miehs <andrew@2sheds.de> wrote:
> What exactly was the three second delay? and what did F5 do to fix this?
>
> Thanks
>
> Andrew

Sorry Andrew for the delay.. I believe I posted this when I first had
the issue, but reposting so that it can be logged

.42 = Squid
.153 = apache web server

"FROM F5"
Looking through cache01-new, every instance of a 3 second delay that I
find, I see where 10.13.200.42 sends the SYN, which is sent through
the BIG-IP to 10.13.200.153. In each instance, I find that
10.13.200.153, rather than replying to the SYN with a SYN-ACK, simply
sends an ACK. This, bing incorrect, gets a RST response from
10.13.200.42. After all, 10.13.200.42 was expecting SYN-ACK, not ACK.
 After a three second delay, 10.13.200.42 initiates the handshake
again, and this time 10.13.200.153 sends the SYN-ACK response, which
allows the handshake to carry on. I had iniitially thought that this
was the fault of 10.13.200.42, but looking over the w04-new tcpdump,
and matching up the delay packets, it's very clear that there is no
SYN-ACK, resulting in this 3 second delay.

As to why 10.13.200.153 would respond to a SYN with just an ACK, I
believe that this may be due to a port reuse issue. The server
believes that port to still be in use, while the BIG-IP believes it to
be closed. To get around this, I would suggest the use of
incrementing autoport, where the BIG-IP does not try to use the same
ephemeral port that the client uses, but rather makes use of some
other ephemeral port. To set this, from the command line issue the
command:

b internal use_incrementing_autoport 1

Which will enable this immediately, and does not require a reboot at all.

"..

Again this fixed the 3 second delay but I still have a ton of
connections sitting in Time_wait on the apache servers. I've tried to
use a sysctl recycle option, but squid via the lb seems to have some
issues with it (again I think it's in the LB)

Tory
Received on Tue Jan 22 2008 - 10:44:55 MST