Arch Linux

kba

Member

Registered: 2008-10-31

Posts: 8

Can't access some hosts via HTTP/SSH randomly

I've got a weird network problem that leaves me baffled, so I turn to you, wise Arch Linux crowd.

After leaving my box running for a while (sometimes after a few hours, sometimes 5+ days), some servers can't be accessed via anything besides ICMP. Unfortunately, the Google domains are part of those, that don't work anymore. I can ping them all right, but when I try to open a web page on one of the affected servers, a timeout error is raised after about a minute. The same goes for access via the tools curl, telnet, ssh, ftp. First I thought this might be a DNS issue, but the host names are resolved correctly (nameservers in /etc/resolv.con set and reachable, ping works).

After rebooting, the problem is gone, I can reach google again without problems. I tried disabling/re-enabling the network interface, I tried deleting all routes and setting them again, I restarted my router - to no avail. I also checked the log files for anything suspicious that might indicate what happens, when the problem occurs, but nothing in them seems to be related. No other box connected to the router experiences this problem.

Also, traceroute is spewing "traceroute: sendto: Network is unreachable" errors when I try to traceroute any server, even for those, that I can still access. This leads me to believe that I have some form of misconfiguration in my network setup. But what? :-)

Here's my setup:
* Router: TP-LINK TL-WR541G/TL-WR542G
* Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 03)
* route -n

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
192.168.1.0     0.0.0.0         255.255.255.0   U     0      0        0 eth0
0.0.0.0         192.168.1.1     0.0.0.0         UG    0      0        0 eth0

* ifconfig eth0

eth0   Link encap:Ethernet  HWaddr XX:XX:XX:XX:XX:XX  
          inet addr:192.168.1.66  Bcast:192.168.1.255  Mask:255.255.255.0
          inet6 addr: fe80::6ef0:49ff:fe0f:426/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:16793 errors:0 dropped:0 overruns:0 frame:0
          TX packets:16914 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:15625507 (14.9 Mb)  TX bytes:2094612 (1.9 Mb)
          Interrupt:45 

At this point, I'm really thankful for any hints, I just don't know what to do anymore. Plus this is a virtually un-google-able problem since I can't reproduce it and it only affects some servers - and google is one of them :-D