[Techtalk] Connectivity Conundrum

R. Daneel Olivaw linuxchix at r-daneel.com
Fri Jul 14 10:05:49 UTC 2006

Hi there,

Le Thu, 13 Jul 2006 21:29:57 +0100
Alexandra OConnor <a.oconnor at keembay.plus.com> a écrit:

> Hi there,
> I'd really appreciate some help with this one!
> The Linux box has correctly got its IP address on startup and I can
> ping the router successfully. So the communication between router and
> my machine seems fine.
> The configuration of Thunderbird and Firefox hasn't changed.
> Any ideas?

Basic network checkup needed :
"ifconfig" to show ip address and netmask
example :

eth0      Link encap:Ethernet  HWaddr 00:0E:A6:37:15:4D
          inet adr:  Bcast:
Masque: adr inet6: fe80::20e:a6ff:fe37:154d/64 Scope:Lien
          RX packets:751 errors:0 dropped:0 overruns:0 frame:0
          TX packets:839 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 lg file transmission:1000
          RX bytes:187372 (182.9 KiB)  TX bytes:71743 (70.0 KiB)
          Interruption:177 Adresse de base:0xe000

sensitive information at :
inet addr, Bcast & Masque (english versions will say 'Netmask' or
something similar)

"netstat -rn" to check gateways
example (again this is in french) :
Destination   Passerelle    Genmask       

sensitive information at the last line :
the default gateway ( should be your internet router

"cat /etc/resolv.conf" to get dns servers
; generated by /sbin/dhclient-script
search somedomain.net

sensitive information :
this file should contain at least 1 "nameserver" line.

cat /etc/hosts just in case somthing evil happened there
# Do not remove the following line, or various programs
# that require network functionality will fail. trantor.r-daneel.net trantor localhost.localdomain localhost

sensitive informaiton :
there should be only the line, not other (well, sometimes
there is one and only one other, but in a dhcp configuration it may
mess up some things)

diagnosis :
you should be able to (in order)
ping the local gateway
ping the dns servers (unless it's also the router)
ping an outside host's ip ('ping')
try a name resolution ('host www.google.com')
try telnet to an outside host ('telnet www.google.com 80')

report in here where it stopped working. If all these steps succeeded,
it means there are application issues, as a proxy web server
configurated into firefox ...

> Thanks in advance and cheers,
> Alexandra

we are made to serve,
(and now it's time for my breakfast ...)

R. Daneel Olivaw,
The Human Robot inside.

More information about the Techtalk mailing list