Telnet startup problem: SERVRFAIL for private subnet PTR query

[apcmeridian]

This all used to worked until yesterday (no telnet delay) and I can't undertand what has changed.

I have a linux with 2 NIC cards: one for my LAN 172.x.x.x (with a DNS server on Windows 2003) and one with my own 10.x.x.x subnet.

Starting today whenever I try to telnet to my 10.1.1.10 device
I see with ethereal the following sequence of DNS packets:
Standard query PTR 10.1.1.10.in-addr.arpa
Standard query PTR 10.1.1.10.in-addr.arpa
Standard query response, Server failure

When I look at the last packet I see:
Server failure (2)
Server is not authority for domain

There is nothing wrong with the DNS server I can ping it, browse the web from my linux, but this query now delays my telnet. Because it worked before I never bother to check what the response from the DNS server was (or rather should be).

This exchange causes me 10 seconds delay for my telnet session to start which as you can imagine is very annoying.

Can anyone help me?

The guy that looks after the windows box say nothing has changed and he doesn't see any errors in the DNS log.

My linux setup looks all good (/etc/resolv.conf) with NICs setup as before the problem started.

 

[brianinms]

Are you trying to telnet by name or IP?

 

[apcmeridian]

I telnet by ip address:
telnet 10.1.1.10

My Linux is RedHat WS4 with standard setup.

 

[brianinms]

What network are you on when you try to telnet to 10.1.1.10?

 

[apcmeridian]

My linux ip is dynamic from dhcp and it has been 172.16.0.79 for a year now.

My ifconfig:
eth0 Link encap:Ethernet HWaddr 00:10:18:27:C0:91
inet addr:172.16.0.79 Bcast:172.16.1.255 Mask:255.255.254.0
inet6 addr: fe80::210:18ff:fe27:c091/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:256919 errors:0 dropped:0 overruns:0 frame:0
TX packets:35984 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:38440749 (36.6 MiB) TX bytes:7318395 (6.9 MiB)
Interrupt:169

eth1 Link encap:Ethernet HWaddr 00:18:8B:7B:4C:22
inet addr:10.1.1.77 Bcast:10.1.1.255 Mask:255.255.255.0
inet6 addr: fe80::218:8bff:fe7b:4c22/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:3830 errors:0 dropped:0 overruns:0 frame:0
TX packets:171 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:245409 (239.6 KiB) TX bytes:32164 (31.4 KiB)
Interrupt:177

 

[brianinms]

So your workstation has 2 network cards and so does your server? I would check the routes on both to ensure your traffic is going out the desired interface.

 

[apcmeridian]

DNS server has one NIC.
My linux has 2 NICs.

My Linux routs look good as well:
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
10.1.1.0 * 255.255.255.0 U 0 0 0 eth1
172.16.0.0 * 255.255.254.0 U 0 0 0 eth0
default 172.16.1.254 0.0.0.0 UG 0 0 0 eth0

When I am on my linux I can telnet to 10.1.1.x address but this DNS query slows me down.

 

[brianinms]

I am confused .... if you are telnetting via IP then DNS is a non issue. DNS is used to resolve Names to IP addresses, hence if you use the IP then DNS isnt part of the equation.

So this is from your server?

My ifconfig:
eth0 Link encap:Ethernet HWaddr 00:10:18:27:C0:91
inet addr:172.16.0.79 Bcast:172.16.1.255 Mask:255.255.254.0
inet6 addr: fe80::210:18ff:fe27:c091/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:256919 errors:0 dropped:0 overruns:0 frame:0
TX packets:35984 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:38440749 (36.6 MiB) TX bytes:7318395 (6.9 MiB)
Interrupt:169

eth1 Link encap:Ethernet HWaddr 00:18:8B:7B:4C:22
inet addr:10.1.1.77 Bcast:10.1.1.255 Mask:255.255.255.0
inet6 addr: fe80::218:8bff:fe7b:4c22/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:3830 errors:0 dropped:0 overruns:0 frame:0
TX packets:171 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:245409 (239.6 KiB) TX bytes:32164 (31.4 KiB)
Interrupt:177



Where and what device is 10.1.1.10

 

[apcmeridian]

Thanks for your help brianinms.
I was able to fix the problem. Somehow a device on the network
corrupted the DNS queries or perhaps confused my DNS server. I will have to investigate further why that is. At least I know how to reproduce it.

 

[apcmeridian]

For anyone that is still reading this thread the correct response from the server should be:
Standard query response, no such name