[VoIP] ENUM (Linux DNS) and Linksys WRT54GS

[Mark Rudholm]

If indeed the problem goes away when you use your ISP's
DNS servers, and you can't get your router's DHCP server
to stop dispensing DNS server info, a better way to prevent
your system's DHCP client from modifying your /etc/resolv.conf
file is to set it immutable with "chattr +i /etc/resolv.conf".

I can help with this problem, but I'm not really connected to
CNET, although you might be able to call me on +1 377 0500

-Mark

Greg Blakely wrote:
> 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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>>
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