Re: Can't get internet working in Linux

From: Moe Trin (ibuprofin_at_painkiller.example.tld)
Date: 02/14/05 

Date: Mon, 14 Feb 2005 14:44:19 -0600

In article <1108367532.461766.227900@l41g2000cwc.googlegroups.com>,
santanu wrote:

>I found that /proc/sys/net/ipv4/tcp_ecn was
>already set to 0. So, that does not seem to
>be the problem.

OK

>Tried setting MTU down to 1490, but the
>problem still persists.

OK

>Anyway, on the bright side I :
> o successfully removed that routing
> line for the 169.254.0.0 'ghost'
> network.

As noted, it's not critical.

> o Chose another host 192.168.10.3 as
> as a gateway (it is in fact a proxy
> server for our network, and its gateway
> is the 192.168.10.9) and could get
> internet by directing my browser to
> this proxy.

Concept problem. The "gateway" is that host that you send packets to that
will forward them to the "other" network (in this case, the world). This is
normally a host with two (or more) network interfaces - one on your net, and
another on a different net that leads to the desired place. Here, you are not
using the gateway, but a proxy service for one application.

> Of course, I still can't
> ping www.google.com.
> Instead I get:
>====
>[santanu@techno santanu]$ ping www.google.com
>PING www.google.akadns.net (64.233.187.104) 56(84) bytes of data.
>>>From 192.168.10.3: icmp_seq=0 Redirect Host(New nexthop: 192.168.10.9)

Exactly - 192.168.10.3 is complaining that you are sending the packets to
the wrong place, and you should send them to 192.168.10.9. See the
"Linux Network Administrator's Guide", which may be on your system, but
can also be found at any LDP mirror or http://tldp.org/guides.html

>Though this solves my problem temporarily,
>I would still like to know what is actually
>preventing it from using the 192.168.10.9
>gateway, especially since the 192.168.10.3
>is a Red Hat 7.3.

192.168.10.3 is just a proxy server for web pages. The World Wide Web is
only one of several thousand network services available, such as DNS, ftp,
finger, telnet, SSH, and on and on (see /etc/services). Do you use a web
browser as a word processor or spread *** application?

In your previous post, you showed

>[root@techno santanu]# traceroute 202.9.145.6
>traceroute to 202.9.145.6 (202.9.145.6), 30 hops max, 38 byte packets
> 1 192.168.10.9 (192.168.10.9) 0.842 ms 0.903 ms 0.793 ms
> 2 static61.11.71-1.dsl-cal.eth.net (61.11.71.1) 37.180 ms 37.484 ms
> 117.395 ms

and that says the routing is correct. It was sending packets on to the
internet (as we see because names are being resolved. The fact that the
192.168.10.3 system can get out (can it also ping?) and your system can
not says there is something different in the configuration. I would
suggest using tcpdump to see what the packets are saying when you try
to _connect_ (not ping) to some web server like google or yahoo.

        Old guy