Linux can't connect to internet with DHCP through Linksys wired router
 

Please help me on this. I have been using Linux for two years and I never came across this problem. It happened about 6 months ago when my family changed their Netgear router to a Linksys router. I have been trying to fix this problem since then. I have tried EVERYTHING!

There are 4 PCs connected, all with Windows except mine. All the windows pcs connect perfectly, except mine. So far I only got access to a Gentoo Live CD because I have just bought a brand new computer so I can't install any utilities. The problem is that my Linux dhcpcd detects everything correctly, but when I try to ping something like yahoo.com or google or msn.com it doesnt work. My router IP is 10.10.10.0 (or 1). My Linux detects everything but I cant connect. Here are outputs of some commands which may aid you in helping me:

ifconfig:
eth0 Link encap:Ethernet HWaddr 00:11:5B:61:63:CC
inet addr:10.10.10.101 Bcast:10.10.10.255 Mask:255.255.255.0
UP BROADCAST NOTRAILERS RUNNING MULTICAST MTU:1500 Metric:1
RX packets:48 errors:0 dropped:0 overruns:0 frame:0
TX packets:15 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:9017 (8.8 Kb) TX bytes:2583 (2.5 Kb)
Interrupt:10 Base address:0xc000

(Theres also the lo interface but i dont think it is needed)

output of cat /etc/resolv.conf
nameserver 206.173.119.72
nameserver 207.155.184.72
nameserver 207.69.188.185
search earthlink.net

route:
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
10.10.10.0 * 255.255.255.0 U 0 0 0 eth0
loopback localhost 255.0.0.0 UG 0 0 0 lo
default 10.10.10.1 0.0.0.0 UG 0 0 0 eth0

arp:
Address HWtype HWaddress Flags Mask Iface
10.10.10.1 ether 00:04:5A:28:93:41 C eth0


I can successfully ping my router, broadcast ping my router, and I can even successfully ping all the nameservers. However, when trying to ping something else, even earthlink.net, it doesn't work. Please help me on this!

Hi ruslan40321, this is basic but it might work, I had a similar probelm when sharing my internet conection, now this is the question, can you ping the other computers in your network? like ping 192.168.0.3 or something like that? if you can that means that you are online, then make sure that you have lisa or rlisa running, and then try it, I know this is basic and maybe you tried it already, I just thought I would tell you in case you did not try it. I hope it works.

Well I know that I am online because I can ping the router and the nameservers... As for lisa,, I have read about it and I dont think I need it because I am not trying to build a network, I just need to connect to the internet (so i can at least install my system). Even if I wanted to, I couldnt try it because my live CD doesnt include lisa or rlisa. Thanks anyway though...

Can you ping yahoo.com or google.com by IP address? Run nslookup and type server to see which nameserver is actually being queried.

I found out the IP address of yahoo on a windows machine and tried pinging it from Linux. It doesnt seem to work, however, it doesnt give me an uknown host error. It just sends packets and doesnt get them back. Packet loss: 100%. I dont have nslookup on the Live CD. Pinging server.earthlink.net didnt work either. Pinging the nameservers themselves however, does work.

Are there enough leases set in the router? I had a buddy that went without for more than two weeks trying to add two comps. to his network and the dhcp on the router was set to only two IP's.

Ok, make sure you have the latest firmware installed for the Linksys router. If you already do, try a hard reset and re-configure the router.

Accessing outside world slow from latest version of M.Linux
 

I am almost facing a similar problem. I am up to date on Mandrake Linux distribution (using urpmi to
download all the latest packages and even the kernel rpms). For some reason, it takes a long
time to connect to any internet site. It takes almost about 4 or 5 minutes to refresh a web page
(say cnn.com).

At home, I use a Airlink wireless router, which in turn connects to the cable modem. The IP I
get for my Linux desktop is a local one issued by the wireless router (with DHCP).
When I ping cnn.com or any other site, it resolves the name very quikclybut later
takes time to get packets from the site. Resolver is not the issue here. nslookup also
queries and gets the IP addresses fast. I used strace to find out where the bottleneck is
when ping is done. It opens a socket, sets options, uses send and when it calls
recvfrom or poll (on a fd), it times out. I have tried this with many other
sites. Ping to the rotuer's IP is fine.

I have dual-boot on my desktop and when I boot to Windows, it works great.
Any idea(s) on what can be done? I have already changed nsswitch.conf to
use only files and dns (for hosts).

Thanks,
Mahesh

I ran into an issue with similar symptoms. What I found *may* be helpful to you.

I am running fc 6 for 64 bit processor on a machine with a K8S-MX motherboard and AMD 3400 64-bit processor. My router is a Linksys BEFSR11 v 2.

Packets were coming in at a trickle with this machine, while the other boxes on my LAN had excellent connectivity.

In my case it was an MTU issue. Running pings to a public IP with different sized packets revealed the problem. I had previouslyheard about linksys MTU issues from one of their tech support guys.

Typical ethernet sized packets:

[root@dyna ~]# ping -s 1500 198.111.176.4
PING 198.111.176.4 (198.111.176.4) 1500(1528) bytes of data.

--- 198.111.176.4 ping statistics ---
3 packets transmitted, 0 received, 100% packet loss, time 2001ms

Smaller packets:

[root@dyna ~]# ping -s 1450 198.111.176.4
PING 198.111.176.4 (198.111.176.4) 1450(1478) bytes of data.
1458 bytes from 198.111.176.4: icmp_seq=1 ttl=245 time=24.7 ms
1458 bytes from 198.111.176.4: icmp_seq=2 ttl=245 time=22.2 ms
1458 bytes from 198.111.176.4: icmp_seq=3 ttl=245 time=24.1 ms
1458 bytes from 198.111.176.4: icmp_seq=4 ttl=245 time=23.3 ms


I manually set the MTU for my NIC and the problem cleared

ifconfig eth0 mtu 1458

My download speeds are now ~ 1 Mbps.

I don't know how to set the MTU as part of the startup process but am sure some Linux gurus that can answer that piece.

For testing I would suggest sticking with the DNS servers that you have already pinged successfully. Many providers block pings to their servers.

Hope this proves helpful.

Dwight

A possible solution
 

Well, I had almost exactly the same problem, and managed to solve it.

The situation, much like yours, was that I had a linksys router (BEFSR41) that I couldn't connect to the internet through with gentoo. I dual-boot with XP, and XP could see the internet just fine; only gentoo was having a problem. The solution that worked for me was to emerge dhcpcd with USE=vfam. I believe that the same effect could be had by running dhcpcd -I, but I can't speak to that.

Anyway, I realize that you posted this well nigh-on three years ago, but hopefully someone will benefit from this post.