[SWLUG] Slow DSL connection (Name resolution??)

[Bryn Reeves]

On 17:06 Sun 11 Jul     , Peter Bradley wrote:
> The router instructions are, of course, Windows only.  They say to
> configure DHCP to "obtain an IP address automatically".  On my Linux box
> dhcpd is not running (neither are named or squid).  dhcpd won't start
> either.  It gives a message saying that DHCP is not configured to listen
> on any ports.

dhcpd is the DHCP server - you don't need it running in order to obtain
address configuration data. Infact, if it was running, it would probably
break stuff - you normally only want one device handing out addresses per
network segment, in this case, that's your router. 

You should see a process called dhclient running, which is the program
which gets the information from the router/dhcp server.

named is likewise a DNS server, which you don't strictly need. RedHat
provides a caching-namserver RPM which implements a simple, local DNS 
cache, SuSE very likely provides something similar, but again, you 
shouldn't need these for good performance on a small home network.

Squid is a caching http proxy ('web cache'), again it can help in some 
situations, but it sounds like you've got other problems here. 

> I have a small Win XP Pro installation, which runs much quicker than the
> Linux installation.
> 
> I'm afraid my knowledge of networking is very limited.  Can anyone point
> me in the right direction on this?

Have you tried dig or ping? dig will query your DNS server directly, it
produces masses of output, but can be very helpful. It should atleast give
an indication of how long DNS queries take.

example:

# dig www.google.com

; <<>> DiG 9.2.3 <<>> www.google.com
;; global options:  printcmd
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 24988
;; flags: qr rd ra; QUERY: 1, ANSWER: 4, AUTHORITY: 11, ADDITIONAL: 11

;; QUESTION SECTION:
;www.google.com.                        IN      A

;; ANSWER SECTION:
www.google.com.         132     IN      CNAME   www.google.akadns.net.
www.google.akadns.net.  594     IN      A       216.239.59.147

<output snipped for brevity>

;; Query time: 30 msec
;; SERVER: 195.112.4.4#53(195.112.4.4)
;; WHEN: Sun Jul 11 19:23:19 2004
;; MSG SIZE  rcvd: 498

You can supply @<server-address> after the name to look up to direct 
it at a particular server. Try your router, then 158.43.240.3, and
see if there's a difference in response time - it may be timing out
on the router, then trying the other address. 

nslookup is another tool you can use to do lookups, but it's 
deprecated as of BIND9 (current version of named & related tools).

'man dig' and 'man ping' will give you the full story on these tools.

I'd try changing your /etc/resolv.conf to use just the ISPs name 
server directly, and ignore your router for now. If that works, it's 
likely a configuration issue on the router. 

On an unrelated note, when starting a new thread on the mailing list,
can you start a new message to discuss at swlug.org.uk, rather than reply
to an existing thread and change the subject line? It messes up mail 
clients which display conversation threads if you do that. (your mail
shows up as a reply to a reply to 'celtic manor MS roadshow' in 
Mutt..)

Kind regards,

Bryn.

> Peter
> 
>