Certain websites very slow or not available through Cisco 2901 Router
Posted on 2011-03-10
I have a strange issue which I've done a lot of research and troubleshooting on but so far to no avail.
Certain websites like yahoo.com, ajc.com, letscelebrateevents.com, etc. either come up very slowly or not at all. Yahoo comes up very slowly except there's no pictures or content, only some links. ajc.com (the local Atlanta newpaper) comes up very slowly with pictures and content. letscelebrateevents.com does not come up at all.
The vast majority of websites come up fine, but there are certain websites critical to our business that will not come up or act like the previous 3 sites I mentioned.
I can traceroute yahoo and ajc.com. When I traceroute letscelebrateevents I get the IP but it times out after a few hops. I cannot ping the IP.
I can telnet on port 80 to yahoo and ajc but not to letscelebrateevents.
Our network consists of a Cisco ASA5510 firewall and a Cisco 2901 Router. The PC's are connected to Cisco stackable switches. We use AT&T Metro E with XO Communications as our ISP. The fiber connects over a patch cable to the router on Gigabit0/0 which connects to the firewall over Gigabit0/1.
I took a laptop and connected it directly to the Gigabit0/1 interface on the router and was still unable to connect properly to those sites. I then connected the same laptop directly via crossover cable to the Fiber ethernet port on the box that AT&T installed, input the proper IP addresses, and tested. All websites came up fine.
I contacted Cisco. The support rep and I repeated my tests. Again while connected directly to the fiber box all websites work fine. While connected directly to the inside interface of the router, those websites would not work correctly.
He says the router config is very basic and tried a few things, none of which resolved the issue. I suggested the router might have a defect.
One other note of interest: Last week, everything suddenly worked fine. A couple days later, it went back to having problems. A day later it worked fine again, but then the next day, those sites were again giving us issues. I had done nothing to the router at all.
It seems to point to some strange glitch in the router. I have even changed the cable from the fiber box to the router and saw no improvement. Rebooting or power cycling the router has no effect.
In summary, gentlemen, I am stumped. The Cisco rep is doing some research and will get back to me tomorrow. Unless you or I or he come up with anything I can only determine that the router must have some defect on the quantum level that hates Yahoo and those other websites.