# [solved] Internet not working after changing ISP

## lucs12

I moved to another place and had to switch to another ISP. Now I don't have any Internet transfer at all on my Gentoo laptop, no ping, nothing. The private LAN and machine settings are the same as before. All my other machines (Windows, MacOS) connect to the Internet with no problems. Any ideas? Thanks.Last edited by lucs12 on Mon May 17, 2010 5:56 pm; edited 1 time in total

----------

## erik258

Hello, 

What are the private lan settings on gentoo, and what are the settings on the other computers?  Also, are you using the same modem/gateway box?  

In gentoo please post the output of ifconfig and route.  If you like you can include /etc/resolv.conf and /etc/conf.d/net too (I assume you tried pinging with an IP address).  

In windows please post the output of the ipconfig command.  I'm afraid I don't know how to get this info from osx, although it's probably the same as in linux.  

I'm guessing that on your linux system something is set statically and so whatever changed, it wasn't picked up by gentoo.  But the configs I've requested can validate that.

----------

## lucs12

The modem is new, but I have the same wireless router. Everything on my LAN is working as before; my Gentoo machine is getting an IP via DHCP on the router and I can transfer files between my machines. All my machines have Internet transfer except my Gentoo laptop, which worked before switching to the new ISP. Yes, I did try to ping an Internet address and got no replies at all.

Gentoo:

ifconfig

eth1      Link encap:Ethernet  HWaddr 00:0e:35:94:07:b5  

          inet addr:192.168.1.51  Bcast:192.168.1.255  Mask:255.255.255.0

          inet6 addr: fe80::20e:35ff:fe94:7b5/64 Scope:Link

          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1

          RX packets:85276 errors:1 dropped:1 overruns:0 frame:0

          TX packets:160988 errors:0 dropped:1 overruns:0 carrier:0

          collisions:0 txqueuelen:1000 

          RX bytes:6191034 (5.9 MiB)  TX bytes:236432726 (225.4 MiB)

          Interrupt:5 Base address:0xc000 Memory:fafee000-fafeefff 

lo        Link encap:Local Loopback  

          inet addr:127.0.0.1  Mask:255.0.0.0

          inet6 addr: ::1/128 Scope:Host

          UP LOOPBACK RUNNING  MTU:16436  Metric:1

          RX packets:40 errors:0 dropped:0 overruns:0 frame:0

          TX packets:40 errors:0 dropped:0 overruns:0 carrier:0

          collisions:0 txqueuelen:0 

          RX bytes:2000 (1.9 KiB)  TX bytes:2000 (1.9 KiB)

route

Kernel IP routing table

Destination     Gateway         Genmask         Flags Metric Ref    Use Iface

192.168.1.0     *               255.255.255.0   U     2000   0        0 eth1

loopback        *               255.0.0.0       U     0      0        0 lo

default         192.168.1.1     0.0.0.0         UG    2000   0        0 eth1

Apple:

ifconfig

lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384

	inet6 fe80::1%lo0 prefixlen 64 scopeid 0x1 

	inet 127.0.0.1 netmask 0xff000000 

	inet6 ::1 prefixlen 128 

gif0: flags=8010<POINTOPOINT,MULTICAST> mtu 1280

stf0: flags=0<> mtu 1280

en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500

	ether 00:1b:63:38:11:24 

	media: autoselect status: inactive

	supported media: autoselect 10baseT/UTP <half-duplex> 10baseT/UTP <full-duplex> 10baseT/UTP <full-duplex,hw-loopback> 10baseT/UTP <full-duplex,flow-control> 100baseTX <half-duplex> 100baseTX <full-duplex> 100baseTX <full-duplex,hw-loopback> 100baseTX <full-duplex,flow-control> 1000baseT <full-duplex> 1000baseT <full-duplex,hw-loopback> 1000baseT <full-duplex,flow-control> none

fw0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 2030

	lladdr 00:1d:4f:ff:fe:71:4d:48 

	media: autoselect <full-duplex> status: inactive

	supported media: autoselect <full-duplex>

en1: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500

	inet6 fe80::21c:b3ff:feb3:3020%en1 prefixlen 64 scopeid 0x6 

	inet 192.168.1.55 netmask 0xffffff00 broadcast 192.168.1.255

	ether 00:1c:b3:b3:30:20 

	media: autoselect status: active

	supported media: autoselect

Thanks for your help.

----------

## krinn

 *lucs12 wrote:*   

> 
> 
> Kernel IP routing table
> 
> Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
> ...

 

your loopback isn't named, so i suppose loopback entry is missing/invalid in /etc/hosts, that might explain loopback isn't using your gateway too. Many applications use "localhost" as loopback name and so might fail if localhost point to nothing.

check that you have

127.0.0.1 localhost entry in your /etc/hosts

and your route will/should look like 

loopback localhost 255.0.0.0 UG

----------

## lucs12

 *krinn wrote:*   

>  *lucs12 wrote:*   
> 
> Kernel IP routing table
> 
> Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
> ...

 

Thanks for pointing this out, however I do have the ''127.0.0.1 localhost'' entry in my /etc/hosts.

----------

## lucs12

Maybe it's an option I didn't select in the kernel config?  :Confused:   I usually compile the kernels I run.

----------

## erik258

Huh, that's weird.  You seem to have everything configured just fine.  Can you ping the other computers on the network?  Maybe it's something stupid like a bad cable or pins in the rj45 port on your network card (if it's wired) getting smashed down - I had a laptop once with that problem; the onboard network managed to get a DHCP lease but it couldn't talk over the network, and it ended up being the pins.  I bet the same could happen with a bad cable.   You might consider swapping the cables with a computer that is known to work and see what happens.  For that matter, it might be fun to take the router out of the equation, and plug the gentoo lappy right into your cable modem.  You should be able to DHCP a public address -- unless you're on a static IP, in which case you know what to do already.  I keep thinking your new ISP is stopping you from using more than 2 computers, even though I can't explain how  or why.  

I think it might be time to apply tracepath (or traceroute if you prefer) to your problem.  This should help you figure out where your packets are dropped -- speaking of which, you don't  have outdated firewall rules, do you?  

Incidentally, if you wanted to look at the routing tables on your OsX machine (pointless as that is, since it looks like your DHCP-provided route is just fine) I think the way to do it, I'm assuming from my BSD experience, is 'netstat -r' or maybe 'netstat -rn' to get numbers rather than irritating words.  

Hope it helps more than the last post!

----------

## krinn

try ping -c1 209.85.229.104 (i wonder how many times a day google.com got ping by testers) to see it's not just a resolver problem.

----------

## lucs12

Apple:

```

traceroute www.google.com

traceroute to www.l.google.com (66.249.81.104), 64 hops max, 40 byte packets

 1  192.168.1.1 (192.168.1.1)  2.379 ms  3.574 ms  0.990 ms

 2  10.67.64.1 (10.67.64.1)  11.613 ms  10.478 ms  10.176 ms

 3  d226-14-45.home.cgocable.net (24.226.14.45)  9.530 ms  10.054 ms  10.107 ms

 4  113-0-226-24.cgocable.net (24.226.0.113)  17.544 ms  15.590 ms  12.330 ms

 5  74.125.49.133 (74.125.49.133)  115.008 ms  21.485 ms  17.157 ms

 6  216.239.47.114 (216.239.47.114)  17.872 ms  11.822 ms  12.696 ms

 7  216.239.46.170 (216.239.46.170)  41.714 ms  33.411 ms  33.097 ms

 8  * * *

 9  lga15s01-in-f104.1e100.net (66.249.81.104)  32.723 ms  31.710 ms  29.980 ms

traceroute 66.249.81.104

traceroute to 66.249.81.104 (66.249.81.104), 64 hops max, 40 byte packets

 1  192.168.1.1 (192.168.1.1)  2.671 ms  2.609 ms  2.068 ms

 2  10.67.64.1 (10.67.64.1)  10.312 ms  11.307 ms  7.973 ms

 3  d226-14-45.home.cgocable.net (24.226.14.45)  8.178 ms  9.709 ms  7.912 ms

 4  113-0-226-24.cgocable.net (24.226.0.113)  12.370 ms  11.454 ms  12.334 ms

 5  74.125.49.133 (74.125.49.133)  12.991 ms  12.373 ms  12.226 ms

 6  216.239.47.114 (216.239.47.114)  14.265 ms  10.628 ms  13.872 ms

 7  216.239.46.170 (216.239.46.170)  32.979 ms  31.722 ms  32.275 ms

 8  * * *

 9  lga15s01-in-f104.1e100.net (66.249.81.104)  38.111 ms  32.288 ms  37.638 ms

ping -c1 www.google.com

PING www.l.google.com (66.249.81.104): 56 data bytes

64 bytes from 66.249.81.104: icmp_seq=0 ttl=56 time=35.841 ms

--- www.l.google.com ping statistics ---

1 packets transmitted, 1 packets received, 0% packet loss

round-trip min/avg/max/stddev = 35.841/35.841/35.841/0.000 ms

```

Gentoo:

```

tracepath www.google.com

gethostbyname: Host name lookup failure

tracepath 66.249.81.104

 1:  192.168.1.51 (192.168.1.51)                            0.262ms pmtu 1500

 1:  192.168.1.1 (192.168.1.1)                              3.073ms 

 1:  192.168.1.1 (192.168.1.1)                             32.409ms 

 2:  10.67.64.1 (10.67.64.1)                               13.465ms 

 3:  24.226.14.45 (24.226.14.45)                           14.465ms 

 4:  24.226.0.113 (24.226.0.113)                           23.606ms 

 5:  no reply

 6:  no reply

 7:  no reply

 8:  no reply

 9:  no reply

10:  no reply

11:  no reply

12:  no reply

13:  no reply

14:  no reply

15:  no reply

16:  no reply

17:  no reply

18:  no reply

19:  no reply

20:  no reply

21:  no reply

22:  no reply

23:  no reply

24:  no reply

25:  no reply

26:  no reply

27:  no reply

28:  no reply

29:  no reply

30:  no reply

31:  no reply

     Too many hops: pmtu 1500

     Resume: pmtu 1500 

ping -c1 www.google.com

ping: unknown host www.google.com

ping -c1 66.249.81.104

PING 66.249.81.104 (66.249.81.104) 56(84) bytes of data.

64 bytes from 66.249.81.104: icmp_seq=1 ttl=56 time=37.3 ms

--- 66.249.81.104 ping statistics ---

1 packets transmitted, 1 received, 0% packet loss, time 0ms

rtt min/avg/max/mdev = 37.372/37.372/37.372/0.000 ms

```

it behaves the same, both directly through the modem and via the router, wired or wireless. And I can ping any other computer on my private network.

Resolver issue? Why did this happen when switching ISPs? How can I fix it? Thanks for all your help, guys.

----------

## lucs12

The problem was my /etc/resolv.conf which pointed to a wrong IP (probably the DNS of my ex ISP) apparently set by dhcpcd back in 2008. I replaced that line in /etv/resolv.conf to ''nameserver 192.168.1.1'' (router's address) and it's working now.

Thanks to erik258 and krinn for pointing me in the right direction.

----------

## erik258

No problem. I love networking. Congratulations!

Incidentally,  *Quote:*   

> 
> 
> Yes, I did try to ping an Internet address and got no replies at all. 

 

I distinguish a hostname like google.com from an address like 74.125.95.99.   Always make sure to test with a known good non-local public IP if a dns hostname doesn't work, and you'll likely find that resolver issues make up a noteworthy percentage of 'connectivity' issues.  They certainly tend to for me!  In fact, I've started using Google's public servers (8.8.8.8, 8.8.4.4) or my own (66.191.143.116) because DNS resolution is so flaky on many public - and even household - networks.

----------

