Strangest thing ever

Hi guys.

I want to discuss something with you guys which have confused us for some time.

Background:
Aftonbladet (one of the biggest newspapers in Sweden), my coworkers at our internal network (and myself) and now a third party UK blogger have reported that everything that loads from script.tailsweep.com or media.tailsweep.comis sluggish or times out. This seems to be true for some users and it seem
to be related to when they sit behind the same firewall/router and get the same external IP.

Today the same problem appeared again and the strangest thing happened. I will try to explain in bullet form.

• I issue GET http://script.tailsweep.com/host.txt which responds lightning fast 1000 times in a row. (host.txt contains the backend hostname so you should get a new one every new request)
• Two of my coworkers do the same without any response at all (same internal network = same IP-address to HAProxy)
  • Debugging - Turning on DEBUG in HAProxy => No connect statements
  • Debugging - Turning on httplog in HAProxy => No matching request (tail -100f /var/log/syslog|grep host.txt)
  • tcpdump - Apparently something bad is happening here (SYN, SYN, SYN, SYN, SYN, SYN, ACK, TCP acked lost segment) but I am no wizard in tcp debugging. I have attached the dump file.
• I can ssh into the machine exit and ssh again without probs
• My coworkers cannot at all.
• We move HAProxy to another machine and the same problems appears there and now we can ssh to the old machine (only when we stop haproxy not before that, even though we have zero traffic now.)

Any ideas anyone ? This is killing me and I hate this so much I can die....buaahahaha. Have never seen something like this..

//Marcus

-- 
Marcus Herou CTO and co-founder Tailsweep AB
+46702561312
marcus.herou#tailsweep.com
http://www.tailsweep.com/
http://blogg.tailsweep.com/




application/octet-stream attachment: tcpdump.out