[olug] Newbie Question

Eli Criffield eli at criffield.net
Thu Jan 12 21:47:32 UTC 2006


How to track down connection issues:

Can you ping the other host?
$ping -c 5 host

(be aware of some firewalls don't allow pings, skip step if so)

if you can ping the other host its probably a firewall issue, yours
(see iptables) or somewhere in between) if not you've got a lower
network problem

Can you ping the default gateway? (Skip if your on the same network)
$ip r
$ping whatever was in the line that started with default

if you can ping your default gateway, are you sure the other host is
up? If it is for sure up, its probably a problem with routing
somewhere (aka call networking)
if you can't ping your default gateway you mite not have your
networking configured right

can't ping anything?
do you have an ip?
$ip a
Do you have a default route at all?
$ip r
Nameservers?
$cat /etc/resolv.conf

if those aren't set find out what they should be and put that in the
proper config file, or if using dhcp start diagnosing that

Do you have a link light on your network card?
$echo go look at the back of your computer

if you don't have a link light, then start trying to figure out why,
most people would say its backwards to put this last, but its the
least likely cause so i never check it first,  under that logic why
not check if the computer is on first?

That's sorta off the top of my head and probably won't make sense when
i try to read it again tomorrow.

Eli



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