Cyrus trying to resolve lan ip

[Russell Packer]

You are correct, the problem is with DNS.

My personal favourite for this one is to run DNS on the machine with empty records for your networks (or real ones, if you like!).

The other option is to use the hosts file.

Finally, you can configure each application (eg. sendmail) not to perform the DNS check.

-----Original Message-----
From: J.A.J. van Belkum [mailto:aukjan at gfo.nl]
Sent: 24 October 2002 14:46
To: info-cyrus at lists.andrew.cmu.edu
Subject: Cyrus trying to resolve lan ip


Hi y'all,

I am running cyrus on a RH7.1 box icw Postfix and MySQL.  All of a 
sudden two of my servers, at different sites started showing  slow 
reaction times (exacly 20 seconds).  They are both connected through the 
same provider.... So I grabbed my tcpdump and started searching.... now 
I got the following dump:

15:14:04.754162 eth1 < 192.168.0.50.1445 > 192.168.0.254.imap: S 18257605:18257605(0) win 8192 <mss 1460,nop,nop,sackOK> (DF)
15:14:04.754288 eth1 > 192.168.0.254.imap > 192.168.0.50.1445: S 3874304414:3874304414(0) ack 18257606 win 5840 <mss 1460,nop,nop,sackOK> (DF)
15:14:04.754692 eth1 < 192.168.0.50.1445 > 192.168.0.254.imap: . 1:1(0) ack 1 win 8760 (DF)
15:14:04.769740 eth0 > 62.177.161.90.2908 > 213.197.28.3.domain: 50561+ PTR? 50.0.168.192.in-addr.arpa. (43) (DF) [tos 0x8] 
15:14:09.775391 eth0 > 62.177.161.90.2910 > 213.197.30.28.domain: 50561+ PTR? 50.0.168.192.in-addr.arpa. (43) (DF) [tos 0x8] 
15:14:12.295410 eth0 > 62.177.161.90.2911 > 213.197.30.28.domain: 7750+ PTR? 50.0.168.192.in-addr.arpa. (43) (DF) [tos 0x8] 
15:14:14.785303 eth0 > 62.177.161.90.2908 > 213.197.28.3.domain: 50561+ PTR? 50.0.168.192.in-addr.arpa. (43) (DF) [tos 0x8] 
15:14:17.305325 eth0 > 62.177.161.90.2909 > 213.197.28.3.domain: 7750+ PTR? 50.0.168.192.in-addr.arpa. (43) (DF) [tos 0x8] 
15:14:19.795301 eth0 > 62.177.161.90.2910 > 213.197.30.28.domain: 50561+ PTR? 50.0.168.192.in-addr.arpa. (43) (DF) [tos 0x8] 
15:14:22.315379 eth0 > 62.177.161.90.2911 > 213.197.30.28.domain: 7750+ PTR? 50.0.168.192.in-addr.arpa. (43) (DF) [tos 0x8]
15:14:24.806469 eth1 > 192.168.0.254.imap > 192.168.0.50.1445: P 1:55(54) ack 1 win 5840 (DF)
15:14:24.807308 eth1 < 192.168.0.50.1445 > 192.168.0.254.imap: P 1:18(17) ack 55 win 8706 (DF)
15:14:24.807411 eth1 > 192.168.0.254.imap > 192.168.0.50.1445: . 55:55(0) ack 18 win 5840 (DF)
15:14:24.807611 eth1 > 192.168.0.254.imap > 192.168.0.50.1445: P 55:243(188) ack 18 win 5840 (DF)
15:14:24.809131 eth1 < 192.168.0.50.1445 > 192.168.0.254.imap: P 18:46(28) ack 243 win 8518 (DF)
15:14:24.813409 eth1 > 192.168.0.254.imap > 192.168.0.50.1445: P 243:267(24) ack 46 win 5840 (DF)
15:14:24.815208 eth1 < 192.168.0.50.1445 > 192.168.0.254.imap: P 46:57(11) ack 267 win 8494 (DF)
15:14:24.815498 eth1 > 192.168.0.254.imap > 192.168.0.50.1445: P 267:279(12) ack 57 win 5840 (DF)
15:14:24.816289 eth1 < 192.168.0.50.1445 > 192.168.0.254.imap: P 57:63(6) ack 279 win 8482 (DF)
15:14:24.816460 eth1 > 192.168.0.254.imap > 192.168.0.50.1445: P 279:298(19) ack 63 win 5840 (DF)
15:14:24.817207 eth1 < 192.168.0.50.1445 > 192.168.0.254.imap: P 63:84(21) ack 298 win 8463 (DF)



It looks like cyrus is trying to resolve the internal IP address... 
which it shouldn't do.  This probabely points to a change in the Network 
of the provider, now that they both take 20 seconds to get answers... 
 Before yesterday they were running just fine, but now I do not want the 
servers to check the DNS records.... How can I do this, or might this be 
some other problem???


bash$ route   
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
62.177.161.88   0.0.0.0         255.255.255.252 U     0      0        0 eth0
192.168.0.0     0.0.0.0         255.255.255.0   U     0      0        0 eth1
127.0.0.0       0.0.0.0         255.0.0.0       U     0      0        0 lo
0.0.0.0         62.177.161.89   0.0.0.0         UG    0      0        0 eth0


Any suggestions are Welcome!!

Thanks,

    Aukjan van Belkum