Can browse Internet but can't ping

ttgump · 2013-08-14 02:16:05

Hi everyone,
I have installed arch linux with kde desktop in my thinkpad-t400 laptop. I delete the netctl and install networkmanager and kde networkmanager applet to configure my network connection. But I have a strange problem: I can browse webpage in firefox and read email using thunderbird, but I just can't ping to any other host. This is the output of ping:

ping -c 3 www.google.com
PING www.google.com (74.125.131.105) 56(84) bytes of data.

--- www.google.com ping statistics ---
3 packets transmitted, 0 received, 100% packet loss, time 2008ms

I can ping localhost only. I think it may be because of the way I set up networkmanager. I followed the steps in this link to set up networkmanager:

http://evilshit.wordpress.com/2012/09/1 … nome3/#ch2

Anyone knows how to solve this problem?

cfr · 2013-08-14 02:33:28

Welcome to the forums.

I recommend using the wiki rather than an outdated guide for a DE you aren't using. (I don't men the "this is deprecated bit" but the "updated" bit also appears to be out of date by now. For example, it ignores the new persistent network naming defaults.)

See https://bbs.archlinux.org/viewtopic.php?id=168162. Not sure it helps but appears to be the same issue.

ttgump · 2013-08-14 03:10:06

Thanks for reply.
I have read the post you mentioned. In that post, the problem is caused by iptables, but I didn't set any rules for iptables in my machine. This is the output of iptables --list:

Chain INPUT (policy ACCEPT)
target     prot opt source               destination         

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination         

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination

r2b2 · 2013-08-14 03:48:55

What kind of connection do you have out to the internet - can other machines on the same network ping ok as perhaps your router is blocking pings or something?

WonderWoofy · 2013-08-14 04:25:27

You're not using Arch in a virtual machine are you?

ttgump · 2013-08-14 05:23:01

I am using wifi to connect to internet. Other people can ping in the same network, so this is the problem of my machine. I am not using arch in virtual machine, I run it on my laptop directly.

Last edited by ttgump (2013-08-14 05:34:20)

cfr · 2013-08-14 21:17:22

If you don't use NetworkManager but bring up the network manually (see the wiki for instructions), can you ping then?

What if you use netctl - can you ping in that case?

ttgump · 2013-08-14 21:45:43

If I use netctl to connect manually I can ping. But netctl can't connect to wifi in my university(it uses wp2 enterprise), so I have to use networkmanager.

cfr · 2013-08-14 21:47:51

I wasn't suggesting it as a solution but as a diagnostic step i.e. now you know the problem is specific to networkmanager. That rules a bunch of other possibilities out.

ttgump · 2013-08-14 21:52:59

Thanks for reply.
Yes, so I think the problem is caused by setting of my software system, not network or hardware problem.

WonderWoofy · 2013-08-14 21:54:35

FYI, I don't think that you should consider using netctl as connecting manually. Connecting manually would be directly using the tools that other network management utilities rely on. So you would use wpa_supplicant to asociate with the network, and then get the ip address, either with dhcp or setting it manually with the iproute2 package.

ttgump · 2013-08-14 21:59:30

Yes. I have disabled dhcpcd and turn off network interface controllers in order to use network management. I used these commands:

disable dhcpcd:

$ sudo systemctl disable dhcpcd.service
$ sudo systemctl disable dhcpcd@.service
$ sudo systemctl stop dhcpcd.service
$ sudo systemctl stop dhcpcd@.service

turn off network interface:

$ ip link set down eth0
$ ip link set down wlan0

cfr · 2013-08-14 23:09:18

WonderWoofy wrote:

FYI, I don't think that you should consider using netctl as connecting manually. Connecting manually would be directly using the tools that other network management utilities rely on. So you would use wpa_supplicant to asociate with the network, and then get the ip address, either with dhcp or setting it manually with the iproute2 package.

Right but if ping works with netctl, that does appear to point to networkmanager, doesn't it? Or do you think netctl might be masking the real problem?

WonderWoofy · 2013-08-15 01:00:48

No, I don't know what the problem is TBH. I just wanted to point that out so that if in the future the OP was asked to try connecting manually, he/she wouldn't just go straight to netctl thinking that was what was implied.

Back to the topic...

ttgump · 2013-08-15 19:29:17

I find a new phenomenon: I can ping when I connect to home wifi (wep or wp2 personal) but I can't ping when I connect to the wifi using entriprise encryption.

WonderWoofy · 2013-08-15 22:34:29

Ping uses ICMP. Is this disabled by the firewall on the network with enterprise encryption?

ttgump · 2013-08-16 02:19:39

But other machine can use ping even with enterprise encryption

cfr · 2013-08-16 02:30:09

So is this a problem only when you use both enterprise encryption and network manager?

That is, if you use the same encryption but not network manager, can you ping?

ttgump · 2013-08-16 02:32:34

So is this a problem only when you use both enterprise encryption and network manager?
- Yes, that's the problem
That is, if you use the same encryption but not network manager, can you ping?
- When I use netctl, I can't connect to enterprise encryption

cfr · 2013-08-16 02:47:49

https://wiki.archlinux.org/index.php/Wi … nual_setup

EDIT: I'm not clear netctl cannot manage that encryption - did you mean wpa2 by any chance? At least, there are instructions for eduroam and netctl uses wpa_supplicant, as far as I know, which can manage this for sure as it is what wicd relies on, too. But it will be better to do it manually in any case.

Last edited by cfr (2013-08-16 02:58:19)

Arch Linux

#1 2013-08-14 02:16:05

Can browse Internet but can't ping

#2 2013-08-14 02:33:28

Re: Can browse Internet but can't ping

#3 2013-08-14 03:10:06

Re: Can browse Internet but can't ping

#4 2013-08-14 03:48:55

Re: Can browse Internet but can't ping

#5 2013-08-14 04:25:27

Re: Can browse Internet but can't ping

#6 2013-08-14 05:23:01

Re: Can browse Internet but can't ping

#7 2013-08-14 21:17:22

Re: Can browse Internet but can't ping

#8 2013-08-14 21:45:43

Re: Can browse Internet but can't ping

#9 2013-08-14 21:47:51

Re: Can browse Internet but can't ping

#10 2013-08-14 21:52:59

Re: Can browse Internet but can't ping

#11 2013-08-14 21:54:35

Re: Can browse Internet but can't ping

#12 2013-08-14 21:59:30

Re: Can browse Internet but can't ping

#13 2013-08-14 23:09:18

Re: Can browse Internet but can't ping

#14 2013-08-15 01:00:48

Re: Can browse Internet but can't ping

#15 2013-08-15 19:29:17

Re: Can browse Internet but can't ping

#16 2013-08-15 22:34:29

Re: Can browse Internet but can't ping

#17 2013-08-16 02:19:39

Re: Can browse Internet but can't ping

#18 2013-08-16 02:30:09

Re: Can browse Internet but can't ping

#19 2013-08-16 02:32:34

Re: Can browse Internet but can't ping

#20 2013-08-16 02:47:49

Re: Can browse Internet but can't ping

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