Re: pppd/chat dialup

From: Moe Trin (ibuprofin_at_painkiller.example.tld)
Date: 07/30/04 

Date: Fri, 30 Jul 2004 15:51:28 -0500

In article <0uadec.lom.ln@pandora.maginfo.net>, Dmitry Davletbaev wrote:
>Hi!
>I try to connect to ISP using pppd and chat:

> noauth

'noauth' should not be needed unless you have a configuration error
elsewhere

> proxyarp

> Cannot determine ethernet address for proxy ARP

You edited the routing table, so I can't tell, but do you have a local
network that _shares_ the same IP addresses with the dialin host?

>so the arp table is empty.

ARP is an Ethernet (and Token-ring) protocol. Hardware addresses (also
called "Media Access Control" or 'MAC' addresses) don't exist on serial
links.

>And when I look at the route table I see this:
>
>Destination Gateway Genmask Flags Metric Ref Use Iface
>212.57.178.254 * 255.255.255.255 UH 0 0 0 ppp0
>default 212.57.178.254 0.0.0.0 UG 0 0 0 ppp0

There should also be a loopback. Is there also an Ethernet LAN as well?
If so, does it have the same address range?

Destination Gateway Genmask Flags Metric Ref Use Iface
212.57.178.254 * 255.255.255.255 UH 0 0 0 ppp0
212.57.178.0 * 255.255.255.0 U 0 0 0 eth0
127.0.0.0 * 255.0.0.0 U 0 0 0 lo
default 212.57.178.254 0.0.0.0 UG 0 0 0 ppp0

ONLY in this case do you need "proxyarp". If the first two lines are
different, like this

212.57.178.254 * 255.255.255.255 UH 0 0 0 ppp0
122.157.78.0 * 255.255.255.0 U 0 0 0 eth0

or if there is no eth0 (or tr0) interface, theen you do NOT want the
proxyarp.

>But I can not connect to any host and when run 'ping 212.57.178.254' I get a
>message that it is unreachable.

I can see no reason for this. If the routing table looks as above, and
the output of /sbin/ifconfig shows the like to be UP, then you should not
get an "unreachable" error. You _may_ get a 100% packet loss (firewall),
but not the "unreachable. I suspect there is something else in your
routing table that effects this.

> When I use Kppp to dial all is OK (except empty arp table), the route
>table in this case:
>
>Destination Gateway Genmask Flags Metric Ref Use Iface
>du-254.178.dial * 255.255.255.255 UH 0 0 0 ppp0
>default du-254.178.dial 0.0.0.0 UG 0 0 0 ppp0

I suspect again, that you deleted something here.

>'ping du-254.178.dial ' leads to nothing (because of no entry in /etc/hosts
>and no specified DNS server, I guess), but 'ping 212.57.178.254' is OK

[compton ~]$ host 212.57.178.254
254.178.57.212.IN-ADDR.ARPA domain name pointer du-254.178.dial.mgn.ru
[compton ~]$

Try to ping du-254.178.dial.mgn.ru ;-) What happened there is that
the route output only allowed 14 characters, but the actual hostnane
is 21 characters long. A piece got chopped off.

Here, you are able to connect to the world, and was able to reach the
name servers. Now, this _could_ be because you have a local LAN, and
have set a "default route" using a host on the LAN. This would be wrong.
Look at the output of '/sbin/route -n' when you are NOT connected to the
telephone. You want to see something like this (assuming you have a
local LAN):

[compton ~]$ /sbin/route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 95017 eth0
127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 420 lo
[compton ~]$

There must not be a line that begins with 0.0.0.0

Hope this helps,

        Old guy

Relevant Pages

  • Re: ip forwarding woes
    ... It turns out routing table on the 10.0.0.2 host was wrong, ... I can ping the firewall at both 192.160.0.1 and 10.0.0.1. ... To UNSUBSCRIBE, email to debian-user-REQUEST@xxxxxxxxxxxxxxxx ...
    (Debian-User)
  • Re: Add route batch file
    ... indivudual host instead of a router) indicates a possible design issue. ... Routing should be done only at the LAN's router,...individual hosts should ... > My office needs a persistant route added to the routing table on all the> workstations. ...
    (microsoft.public.win2000.networking)
  • Re: [opensuse] Advanced postfix question: IP and reverse DNS
    ... Host or domain name not found. ... Name service error ... Postfix didn't support sender based routing before version 2.3. ...
    (SuSE)
  • Re: AT&T Wireless GPRS networking with Merlin G100 card
    ... >>Now, the gateway is a host address, which already has routing via eth0. ... Is the Ethernet connection a point-to-point connection ... tauno voipio iki fi ...
    (comp.os.linux.networking)
  • Re: [SLE] SAMBA Problem
    ... The netmask shown is surely not the reason why he cannot talk to ... There is no need for any routing protocols ... is far from the only possible reason for failure to reach a local host. ...
    (SuSE)