[Pdns-users] Possible tcp listener issue

[Simon Bedford]

Hi Bert,

We have one of the instances on our non live server happening at the 
moment so I have not restarted it as yet, I have performed the following 
on it and recorded the responses :-

UDP REQUEST
ptn-cdns03:/usr/local/nagios/libexec# dig google.com @212.159.6.117 any

; <<>> DiG 9.5.1-P3 <<>> google.com @212.159.6.117 any
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 27597
;; flags: qr rd ra; QUERY: 1, ANSWER: 4, AUTHORITY: 0, ADDITIONAL: 4

;; QUESTION SECTION:
;google.com.			IN	ANY

;; ANSWER SECTION:
google.com.		26792	IN	NS	ns2.google.com.
google.com.		26792	IN	NS	ns4.google.com.
google.com.		26792	IN	NS	ns1.google.com.
google.com.		26792	IN	NS	ns3.google.com.

;; ADDITIONAL SECTION:
ns4.google.com.		81336	IN	A	216.239.38.10
ns2.google.com.		81336	IN	A	216.239.34.10
ns3.google.com.		81336	IN	A	216.239.36.10
ns1.google.com.		81336	IN	A	216.239.32.10

;; Query time: 3 msec
;; SERVER: 212.159.6.117#53(212.159.6.117)
;; WHEN: Tue Mar 30 14:49:06 2010
;; MSG SIZE  rcvd: 164

TCP REQUEST
ptn-cdns03:/usr/local/nagios/libexec# dig +tcp google.com @212.159.6.117 any

; <<>> DiG 9.5.1-P3 <<>> +tcp google.com @212.159.6.117 any
;; global options:  printcmd
;; connection timed out; no servers could be reached

Netstat shows it to be still listening:-

ptn-cdns03:/usr/local/nagios/libexec# netstat -anp | grep LISTEN | grep 
"212.159.6.117:53 "
tcp        0      0 212.159.6.117:53        0.0.0.0:* 
LISTEN      14214/pdns_recursor

Telnet shows the socket to be there :-

ptn-cdns03:/usr/local/nagios/libexec# telnet 212.159.6.117 53
Trying 212.159.6.117...
Connected to 212.159.6.117.
Escape character is '^]'.

Pressing enter has no effect on this also.

This happens on port 53, 5300, 5301, etc as we use different ports for 
some of our services whereas udp works fine on all ports.

Hope this info is useful

Simon