[lug] DNS Problems: Is it me, or is it Comcast?

[Jason Davis]

http://www.dnsreport.com/tools/dnsreport.ch?domain=cleansoft.com

On Mon, 2004-10-04 at 09:33, Michael Deck wrote:
> I started having some DNS problems on Friday morning, and I need help 
> determining whether it's in the name server that I administer, or whether 
> it's entirely a Comcast problem (and what I might suggest they do about it).
> 
> Here are the details. On Friday morning I noticed I was unable to ping my 
> remote server (cleansoft.com) by name but I could ping it by IP address 
> (198.49.126.122). This from my home office, which has Comcast "business" 
> cable internet. The remote host is running KRUD FC1 and is authoritative 
> for cleansoft.com.
> 
> I also noticed I could ping the server by name from the host of one of my 
> clients. At first I thought that this was a DNS refresh problem, or maybe 
> an iptables problem, but I think I've convinced myself it isn't iptables.
> 
> If I put 198.49.126.122 in /etc/resolv.conf as a nameserver, my local 
> problems go away. Emails appear to be reaching me from everywhere except 
> other comcast users.
> 
> What I don't know is whether my zone files are somehow causing the problem. 
> Here is another tidbit that worries me. When I use
> 
>    host -v -C cleansoft.com
> 
> from my client's system,
> 
>   > host -v -C cleansoft.com
>   Trying "cleansoft.com"
>   Received 121 bytes from xxx.xx.xxx.x#53 in 7 ms
>   Trying "cleansoft.com"
>   ;; connection timed out; no servers could be reached
> 
> where I've blunked out my client's DNS host address. So what does this 
> mean? I thought -C meant to try to find the authoritative nameserver.
> 
> Here is my zone file for cleansoft.com. Note, this setup has been working 
> for a couple of months until Friday morning, and I haven't changed anything 
> related to BIND that I am aware of, though there may have been a system 
> reboot in there that I don't know about. I checked my record with my domain 
> registrar, and it shows ns1.cleansoft.com 198.49.126.122 as primary 
> nameserver for this domain.
> 
> cleansoft.com.  IN SOA  ns1.cleansoft.com. postmaster.cleansoft.com. (
>                                  6       ; Serial
>                                  10800   ; Refresh after 3 hours
>                                  3600    ; Retry after 1 hour
>                                  604800  ; Expire after 1 week
>                                  86400   ; Minimum TTL of 1 day
> )
> 
> cleansoft.com.  IN NS   ns1.cleansoft.com.
> cleansoft.com.  IN NS   ns2.cleansoft.com.
> 
> ;
> ; Host addresses
> ;
> 
> localhost.cleansoft.com.        IN A    127.0.0.1
> www.cleansoft.com.              IN A    198.49.126.122
> cleansoft.com.                  IN A    198.49.126.122
> mail.cleansoft.com.             IN A    198.49.126.122
> ns1.cleansoft.com.              IN A    198.49.126.122
> ns2.cleansoft.com.              IN A    198.49.126.122
> cleansoft.com.                  IN MX   0 cleansoft.com.
> 
> 
> 
> Michael Deck
> Cleanroom Software Engineering, Inc.   
> 
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