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2600Plus PTR query mangled

  • hairymonster
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11 Aug 2011 01:14 #68996 by hairymonster
2600Plus PTR query mangled was created by hairymonster
Ok, so it's old but it works... until today...

Whenever a PTR is queried, the first query comes back with the correct info, and any subsequent ones come back with that same info for different addresses. Example:
ping -a 8.8.8.8 will result in google-public-dns-a.google.com
Then ping -a x.x.x.x will also result in google-public-dns-a.google.com!

This appears to persist until a reboot, when the same behaviour can be observed again.

The full response string from an nslookup of type=ptr is:
255.255.255.255.in-addr.arpa name = google-public-dns-a.google.com

Every response appears to come back as a query of 255.255.255.255. A Wireshark trace reveals that the router believes the machine has queried 255.255.255.255, and returns a constant result.

Upstream DNS servers are responding correctly.

Does anyone have a 2600Plus in operation that can confirm this behaviour?

Debug from nslookup is below, where you can see that the question 8.8.8.8.in-addr.arpa mysteriously changes to 255.255.255.255.in-addr.arpa - securehotmail.net was the first PTR query after a reboot of the router:

> set debug
> set d2
> set type=ptr
> 8.8.8.8
Server: [172.29.0.1]
Address: 172.29.0.1



SendRequest(), len 38
HEADER:
opcode = QUERY, id = 19, rcode = NOERROR
header flags: query, want recursion
questions = 1, answers = 0, authority records = 0, additional = 0

QUESTIONS:
8.8.8.8.in-addr.arpa, type = PTR, class = IN





Got answer (80 bytes):
HEADER:
opcode = QUERY, id = 19, rcode = NOERROR
header flags: response, auth. answer, want recursion, recursion avail.
questions = 1, answers = 1, authority records = 0, additional = 0

QUESTIONS:
255.255.255.255.in-addr.arpa, type = PTR, class = IN
ANSWERS:
-> 255.255.255.255.in-addr.arpa
type = PTR, class = IN, dlen = 19
name = securehotmail.net
ttl = 60 (1 min)



255.255.255.255.in-addr.arpa
type = PTR, class = IN, dlen = 19
name = securehotmail.net
ttl = 60 (1 min)
>

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11 Aug 2011 15:18 #69006 by rothers
Replied by rothers on topic Re: 2600Plus PTR query mangled

HairyMonster wrote: Does anyone have a 2600Plus in operation that can confirm this behaviour?


Yes, don't think these bugs ever got fixed in the 2600+ DNS proxy. Our fix was to not use it but to specify ISPs DNS servers directly.

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