Can't access a website

[kostas]

Using Ubuntu Dapper, and Firefox I can't access the site www.contra.gr

I've tried other browsers and it doesn't work.

Pinging it works fine but a tracepath stops at the 14th hop and then nothing.

Other computers work fine on the same LAN.

The HOSTS file is clear.

What else can I try?

 

[horndude]

check the resolv.conf file and make sure dns numbers are present

as root run the route command w/o any options, make sure the routing table is correct

 

[kostas]

DNS is fine.

Route table looks thin...

Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
localnet * 255.255.255.0 U 0 0 0 eth0
default home 0.0.0.0 UG 0 0 0 eth0

 

[Law]

So you can ping www.contra.gr and get a reply? But you can't access it through a web browser?

 

[kostas]

correct.

PING contra.gr (89.234.32.242) 56(84) bytes of data.
64 bytes from migration1.contra.gr (89.234.32.242): icmp_seq=1 ttl=114 time=109 ms
64 bytes from migration1.contra.gr (89.234.32.242): icmp_seq=2 ttl=114 time=111 ms
64 bytes from migration1.contra.gr (89.234.32.242): icmp_seq=3 ttl=114 time=108 ms
64 bytes from migration1.contra.gr (89.234.32.242): icmp_seq=4 ttl=114 time=186 ms
64 bytes from migration1.contra.gr (89.234.32.242): icmp_seq=5 ttl=114 time=106 ms
64 bytes from migration1.contra.gr (89.234.32.242): icmp_seq=6 ttl=114 time=121 ms
64 bytes from migration1.contra.gr (89.234.32.242): icmp_seq=7 ttl=114 time=106 ms

--- contra.gr ping statistics ---
7 packets transmitted, 7 received, 0% packet loss, time 7406ms
rtt min/avg/max/mdev = 106.661/121.626/186.644/26.968 ms

 

[Law]

It's an application problem, more likely a firewall or the browser setting. Does Ubuntu have a firewall enable, not sure about it since I don't use it.

Things to check are the proxy setting, if you configure the Ubuntu to connect to a proxy server, that's one of the reason why you can ping but can't use the browser.

Browser setting may inherit the proxy setting. Check the options. Firefox options should be in edit>preference>general tab>connection settings

 

[kostas]

No, I'm sure I'm not using a proxy to connect. There's a firewall enabled but disabling it still gives me the same results. Also, here's what Ethereal caught while trying to connect to the site:

 

[Law]

Disable the firewall and make sure it doesn't start during reboot, now reboot your machine and see what happens.

I'm not an expert or anything at analyzing packets, but what you're showing me is a TCP three-way handshake gone wrong.

From the second and third packet: The second packet which is the server respond with it's sequence and maximum segment size to your computer, then the third is the same thing, but look at the time between the second and the third. That mean there was a delay and the web server initiated a second transmission because it didn't get an acknowledgment from your computer. Then the fourth, that's your computer trying to respond to the web server that it didn't receive an respond and to redo the handshake again. If you can't communicate with the web server, it's going to be like that forever. This sounds a lot like a firewall problem.

I'm not that good at analyzing packets yet, but that's just something I believe is going on.

 

[kostas]

i'm thinking of lowering the mtu to 1380 to see if that's gonna help.

 

[Law]

I doubt changing the MTU is going to help.

Is it only with this web site? and it's only with your computer on Linux? If you dual boot, would Windows be able to access the web site?