network problems can't ping or sync pacman

boom · 2008-02-11 01:40:11

Hello all, I'm new to Arch and I'm having issues with my networking.

I'm trying to connect to the lan at my college using dhcp. I've read the newbie guide and my rc.conf and hosts are configured correctly. resolv.conf is being generated by dhcpcd.

When I try and ping www.google.com I get 100% packet loss. When I try and ping any of my colleges websites everything worked fine.

When I try and run pacman -Sy I get the following:

warning: current locale is invalid; using default "C" locale
:: Synchronizing package databases...
error: failed retrieving file 'core.db.tar.gz' from ftp.nethat.com : Not logged in
error: failed to synchronize core: Not logged in
error: failed retrieving file 'extra.db.tar.gz' from ftp.nethat.com : Not logged in
error: failed to synchronize core: Not logged in
error: failed retrieving file 'community.db.tar.gz' from ftp.nethat.com : Not logged in
error: failed to synchronize core: Not logged in
error: failed to synchronize any databases

I've also double checked that I uncommented the correct locale in locale.gen.

Networking in rc.conf looks like this:

HOSTNAME="minerva"
lo="lo 127.0.0.1"
eth0="dhcp
INTERFACES=(lo eth0)
gateway="default gw 192.168.0.1"
ROUTES=(!gateway)

hosts looks like:

127.0.0.1 localhost.localdomain localhost minerva

Any help would be greatly appreciated.

Misfit138 · 2008-02-11 01:50:39

What happens when you run 'locale-gen' as root?

Also, you are missing a quote mark on your eth0= line.
Is your gateway actually 192.168.0.1? Or did you just leave the default? I'm just guessing, but if you are on a college lan, I don't think the default gateway would be 192.168.0.1.
What is the output from 'ifconfig eth0' ?
You might try just simplifying your rc.conf like this:
eth0="dhcp"
INTERFACES=(eth0)
ROUTES=(!gateway)
And comment out the gateway line.
Also, I get the same error on nethat.com mirror. Try another mirror. Easynews works well.
After editing your rc.conf, restart network with

# /etc/rc.d/network restart

And retry pinging google.

boom · 2008-02-11 02:31:51

Lots of answers to lots of questions. Thanks for the quick help.

Changing the mirror got pacman to sync correctly. That's pretty neat. But I still can't ping, still 100% loss. I installed lynx just to see if I could browse the internet and I could.

When I run locale-gen I get the following:

Generating locales...
en_US.UTF-8... done
Generating complete.

I missed the quote in my copying, my rc.conf is fine... oops

I just left the default for my gateway.

The output from ifconfig eth0 is (I'm messing up the formatting so it is easier to type):

eth0
Link encap:Ethernet HWaddr 00:16:CB:9C:A3:45
inet addr:XXX.XXX.144.221 Bcast:XXX.XXX.151.225 Mask:255.255.248.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:30976 errors:0 dropped:0 overruns:0 frame:0
TX packets:58 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:6643659 (6.3 Mb) Tx bytes:4928 (4.8 Kb)
Interrupt:16

Last edited by boom (2008-02-11 02:44:20)

Misfit138 · 2008-02-11 02:39:14

Ok, well, just to neaten things up, comment out the default gateway for now.
Since you can't ping www.google.com, but you have an IP address, I am guessing this is a DNS issue.
Try this. Edit your /etc/conf.d/dhcpcd and edit the line that looks like this:

DHCPCD_ARGS=" -t 30 -h $HOSTNAME"

and make it look like this:

DHCPCD_ARGS="-R -t 30 -h $HOSTNAME"

That will prevent /etc/resolv.conf from being overwritten by dhcpcd on each network startup.
Then, edit /etc/resolv.conf to look like this:

nameserver 208.67.222.222
nameserver 208.67.220.220

Restart network:

# /etc/rc.d/network restart

And try again.

boom · 2008-02-11 02:51:16

Still no ping, 100% packet loss.

My arch box is a macbook pro does that matter?

Misfit138 · 2008-02-11 02:56:49

boom wrote:

Still no ping, 100% packet loss.

I'm stumped. A more advanced user than myself must take a crack at it.

So you cannot get out on the net beyond your college local sites? Or, you just can't ping? Can you ping IP addresses? Like 4.2.2.1 ?

boom · 2008-02-11 03:05:34

Using lynx the text based browser I can browse the internet. However my ping to any website or ip address other than my own and my college's gets 100% packet loss.

Weird.

Do you think this problem will bite me in the future if I ignore it and start installing software I need?

Thanks for all your help.

Misfit138 · 2008-02-11 03:10:00

If it were me, I wouldn't worry about it..at least for now.
I'm sure a more experienced user will have a better answer.
Enjoy Arch!

peart · 2008-02-11 03:11:01

It sounds like your college blocks ICMP ping requests/replies. I'd ignore it and continue installing. It's definitely not DNS, because you were able to sync pacman using easynews, and are able to browse with lynx.

The only other thing I can think of, but it's a long shot, is that your iptables setup is blocking ICMP too aggressively. Do you have iptables running?

slackhack · 2008-02-11 03:12:50

So you can connect to the internet and sync with arch mirrors, but you just can't ping? could you ever ping, i.e., do you or does your college have a firewall set up that's perhaps blocking outgoing pings?

Misfit138 · 2008-02-11 03:14:09

Just a sidenote, I believe the nethat error may be related to an upstream wget issue, having to do with not providing username/pw. Aria might work..

boom · 2008-02-11 03:54:03

peart wrote:

It sounds like your college blocks ICMP ping requests/replies. I'd ignore it and continue installing. It's definitely not DNS, because you were able to sync pacman using easynews, and are able to browse with lynx.
The only other thing I can think of, but it's a long shot, is that your iptables setup is blocking ICMP too aggressively. Do you have iptables running?

I uninstalled iptables for fear of something like that.

It's looking like my college does not allow pinging(I can't ping from this box). I had no idea. Oops. Why would someone block pinging?

Anyway, thanks for all of your help everyone. I look forward to a full install of Arch! I still have a while to go.

peart · 2008-02-11 04:21:21

boom wrote:

Why would someone block pinging?

I know of 3 reasons, but one isn't really up to date:
1) It's a way of stealthing computers. If a hacker can ping you, then he knows you are there, and can begin looking for vulnerabilities.
2) It prevents the world from pinging you like crazy (denial of service).
3) The old ping of death vulnerability (pinging with a packet size of 65535, if memory serves me correctly). This used to crash computers before, but it's been fixed in every self-respecting OS.

Good luck with the rest of your install.

slackhack · 2008-02-11 22:35:58

peart wrote:

boom wrote:
Why would someone block pinging?
I know of 3 reasons, but one isn't really up to date:
1) It's a way of stealthing computers. If a hacker can ping you, then he knows you are there, and can begin looking for vulnerabilities.
2) It prevents the world from pinging you like crazy (denial of service).
3) The old ping of death vulnerability (pinging with a packet size of 65535, if memory serves me correctly). This used to crash computers before, but it's been fixed in every self-respecting OS.
Good luck with the rest of your install.

those are good reasons to block pinging in, but maybe not for why someone would block pinging out. maybe the U wants to prevent students from trying DOS ping attacks on outside computers to protect against liability? :?:

Sjoden · 2008-02-11 23:33:43

Off topic, just discussing, but not replying to pings(icmp requests) on a personal computer wouldn't necessarily stop a DoS attack, and most likely not a Distributed DoS. The networking card and firewall still have to accept and read the packet and then decide what to do, so it still takes up some services/bandwidth. Now if a major ISP decided to block icmp requests/replies on an interface in there network/backbone with a much higher bandwidth, that could prevent a DoS attack on their downstream customers...

@Slackhack, thats very likely considering some of the students at colleges and universities.

Last edited by Sjoden (2008-02-11 23:34:22)

Arch Linux

#1 2008-02-11 01:40:11

network problems can't ping or sync pacman

#2 2008-02-11 01:50:39

Re: network problems can't ping or sync pacman

#3 2008-02-11 02:31:51

Re: network problems can't ping or sync pacman

#4 2008-02-11 02:39:14

Re: network problems can't ping or sync pacman

#5 2008-02-11 02:51:16

Re: network problems can't ping or sync pacman

#6 2008-02-11 02:56:49

Re: network problems can't ping or sync pacman

#7 2008-02-11 03:05:34

Re: network problems can't ping or sync pacman

#8 2008-02-11 03:10:00

Re: network problems can't ping or sync pacman

#9 2008-02-11 03:11:01

Re: network problems can't ping or sync pacman

#10 2008-02-11 03:12:50

Re: network problems can't ping or sync pacman

#11 2008-02-11 03:14:09

Re: network problems can't ping or sync pacman

#12 2008-02-11 03:54:03

Re: network problems can't ping or sync pacman

#13 2008-02-11 04:21:21

Re: network problems can't ping or sync pacman

#14 2008-02-11 22:35:58

Re: network problems can't ping or sync pacman

#15 2008-02-11 23:33:43

Re: network problems can't ping or sync pacman

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