Re: [Ldapdns-users] ICMP Destination Unreachable, Port 53 Unreachable

[Mark B. <ma...@ib...>]

James,

Thanks for your reply.

I used tcpdump on the server (tcpdump -i eth0 udp and port 53 or icmp -w
dns.cap) and used ethereal to get a look at the capture. I found that
there is no pattern to the sending of the icmp packets and that they do
originate from the DNS server.
@4000000043e0238b1c316264 ldapdns info: starting ldapdns 2.06 (1:1/128)
The only thing odd in the logs is that this line shows up randomly:

@4000000043e0238b1c316264 ldapdns info: starting ldapdns 2.06 (1:1/128)

and I feel that it could be in the same pattern as the icmp packets.

This section of an strace shows a segmentation fault.

@4000000043e02b0000848ba4 write(4, "0\201\204\2\1\4c\177\0049dc=ns1,
dc=ibc, dc=com"..., 135) = 135
@4000000043e02b00009bfba4 recvfrom(3, "F\212\0\0\0\1\0\0\0\0\0\1\3ns1
\3ibc\3com\2au\0\0\34\0\1"..., 512, 0, {sa_family=AF_INET,
sin_port=htons(1368), sin_addr=inet_addr("202.74.164.1")}, [16]) = 43
@4000000043e02b00009f5aec time([1138764534])                      =
1138764534
@4000000043e02b0000a38554 time(NULL)                              =
1138764534
@4000000043e02b0000a6a61c write(4, "0\201\204\2\1\5c\177\0049dc=ns1,
dc=ibc, dc=com"..., 135) = 135
@4000000043e02b0000d63db4 recvfrom(3, 0x805fc7a, 512, 0, 0xbffffc30,
0xbffffc2c) = ? ERESTARTSYS (To be restarted)
@4000000043e02b0000e0059c --- SIGSEGV (Segmentation fault) @ 0 (0) ---
@4000000043e02b0000eeaf84 +++ killed by SIGSEGV +++
@4000000043e02b002346d0ac execve("/bin/ldapdns", ["/bin/ldapdns"], [/*
12 vars */]) = 0
@4000000043e02b00234eb81c uname({sys="Linux", node="ns2", ...})   = 0
@4000000043e02b002352b3a4 brk(0)                                  =
0x805edc4
@4000000043e02b0023550d34 old_mmap(NULL, 4096, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x40017000

I am assuming a SIGSEV isn't normal and for some reason my ldapdns is
dying on both my name servers. They are both Debian Sarge.

Mark.


On Tue, 2006-01-31 at 23:26 +1100, sys...@su... wrote:
> Hi Mark,
> 
> Sorry if you've tried and discounted this, but are you certain this is
> actually coming from ldapdns?  Can you see strace output or similar that
> will confirm this?  How often does it occur?  Can you rely on it occurring
> say, once an hour, once a day, etc?  It just sounds extremely odd to me
> that an application would respond in this manner, it's not correct
> behaviour, and not by omission or error, it's something the app has to go
> out of its way to do.  Can you categorically eliminate factors like the
> firewall on the box, firewalls upstream of the box, etc?
> 
> Again, sorry if you've gone through all this, but it does sound very
> strange to me.
> 
> Cheers,
> James.
> 
> >
> > Greetings,
> >
> > I am using ldapdns-2.05 with openldap 2.3.13 and have found that
> > occasionally the server will return a port unreachable for udp port 53.
> > I am trying to discover if this is normal behaviour as it has not caused
> > and serious issues yet but a minor issue did come up because of this.
> >
> > There seems to be no pattern, it will send this message at random for
> > any type of query.
> >
> > Mark.
> >
> >
> >
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> 
> 
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-- 
Regards,

Mark Burring
Systems Administrator
Internet Business Corporation
http://www.ibc.com.au/
Ph. 08 9228 9922
Fx. 08 9228 9044
mar...@ib...