[VoIP] ENUM (Linux DNS) and Linksys WRT54GS

[Greg Blakely]

Even though others seem to disagree, I think that it has something to do
with DHCP.

In a static IP situation, your entries in /etc/resolv.conf would always
be there exactly as you entered them.  This would include your ISP's DNS
server, and other optional information.

But, by using DHCP, the /etc/resolv.conf is overwritten by whatever
information your DHCP server provides.  If I understand you correctly,
it is your router that is acting as a DHCP server, and it is handing out
its own IP address as being the DNS server.

So, I zero in on the DHCP server.  Two thoughts occur to me.  Either (a)
the DHCP server doesn't know how to deal with NAPTR DNS resource
records, or (b) it doesn't have an upstream DNS server that it queries
that responds in a timely manner.

A way around this would be to have a file that you save as a template
for the /etc/resolv.conf, and then copy it over (via cron) from time to
time to your /etc/resolv.conf.

Example:  Create a file in /etc that is named resolv.template.  In this
file, have something like the following:

nameserver 199.191.128.103
nameserver 199.191.128.104 



Then, set up a cron job to overwrite your resolv.conf a few times per
day:

# crontab -e

4 * * * * cd /etc; rm -f resolv.conf; cp resolv.template resolv.conf



See if that helps at all.

> -----Original Message-----
> From: voip-bounces at ckts.info [mailto:voip-bounces at ckts.info] 
> On Behalf Of Chad Perkins
> Sent: Saturday, January 05, 2008 10:57 AM
> To: Voice Over IP Tandem for Analog Switches
> Subject: Re: [VoIP] ENUM (Linux DNS) and Linksys WRT54GS
> 
> The problem seems to be in Linux.  I think what's happening 
> is that Enumlookup (a DNS query) is timing out before getting 
> an answer (Asterisk does hang for a minute on the EnumLookup).
> 
> The larger problem I think is even pinging is very slow by name (i.e. 
> std.ckts.info).  Connections made by IP address are just as 
> fast as before, even to the same site(s).  This problem seems 
> to be effect all applications that use DNS, except nslookup!!?
> 
> Chad
> 
> On 5 Jan 2008 at 1:02, Greg Blakely wrote:
> > Chad,
> > I can email you a copy of my "dc" macro.  It works on those 
> versions 
> > of Asterisk 1.4 that don't have a broken ENUM function.  
> Let me know.
> > Greg
> 
> > > -----Original Message-----
> > > From: voip-bounces at ckts.info [mailto:voip-bounces at ckts.info] On 
> > > Behalf Of Chad Perkins
> > > Sent: Friday, January 04, 2008 10:54 PM
> > > 
> > > I'm in day 3 of not being able to make calls on CNET due to a 
> > > failure of Linux DNS after a reboot of the box and replacing the 
> > > VeriZon DSL router with a WRT54GS...
> > > 
> > > Tonight I flashed the firmware on the Linksys from 1.50.6 to
> > > 1.52.2 (the latest?) to no avail.
> > > 
> > > I'm off to bed now, but if any you Linux "gurus" think you can 
> > > figure how how to fix this I'd love to hear from you tomorrow 
> > > (1-955-9924)!
> > > Chad
> 
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