DNS via ADSL modem/router doesn't play well with DHCP

Neil Woolford neil at neilwoolford.co.uk
Sat Oct 8 14:14:14 UTC 2005


I have a Linksys ADSL2MUE modem, running into a WRT54G wireless/wired
router.

Currently the modem is set as DHCP server and gateway between local
network and internet.  The modem picks up all the appropriate
information from the ISP, including the two static DNS addresses.  It
then sets up attached computers via DHCP with itself as DHCP server,
gateway address *and* DNS server address.  (All 192.168.1.1).

My laptop, running Windows 98SE, works flawlessly with this and has no
trouble reaching the DNS via the local alias.  Winipcfg shows
192.168.1.1 as the DNS address.  So it appears that the modem/router is
forwarding domain name queries from the windows machine to the real DNS
addresses that it has obtained from the ISP and is then passing the
results back.

Unfortunately this doesn't work under Ubuntu (Breezy preview, 5.10 at
the moment but also previous versions).  Domain name queries to
192.168.1.1 just don't get answered.  Manually inserting the ISP
provided DNS addresses via the System>~Administration>Network gui gets
the system going again, but is overwritten the next time DHCP leases are
renewed.

I have followed the instructions on Dennis Kaarsemaker's wiki page
https://wiki.ubuntu.com/StaticDnsWithDhcp and set the system to prepend
the static DNS addresses and not overwrite them, so I do have a working
fix for the problem as far as my desktop machines go.

My question really is;  are others experiencing similar problems, or is
the difficulty a peculiarity of the Linksys ADSL2MUE?  If the problem is
widespread, can anything be done to fix it without editing config files?

Neil





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