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Dec 09 2011

No working DCC servers

I am running my mail server on Ubuntu Server 10.10 x64.
It seems from time to time my mail log is recording this message :

Dec  7 07:50:59 evilbox dccproc[1175]: no working DCC servers dcc1.dcc-servers.net dcc2.dcc-servers.net dcc3.dcc-servers.net ... at 127.0.0.1
Dec  7 07:55:12 evilbox dccproc[1175]: no working DCC servers dcc1.dcc-servers.net dcc2.dcc-servers.net dcc3.dcc-servers.net ... at 127.0.0.1

Running cdcc info gives this :

# cdcc info


# 12/07/11 09:42:21 EET  /var/dcc/map
# Re-resolve names after 11:31:25  Check RTTs after 09:46:25
# 1 total, 0 working servers
IPv6 on   version=3

dcc1.dcc-servers.net,-      RTT+1000 ms  anon
#   undefined name or wrong IP version

dcc2.dcc-servers.net,-      RTT+1000 ms  anon
#   undefined name or wrong IP version

dcc3.dcc-servers.net,-      RTT+1000 ms  anon
#   undefined name or wrong IP version

dcc4.dcc-servers.net,-      RTT+1000 ms  anon
#   undefined name or wrong IP version

dcc5.dcc-servers.net,-      RTT+1000 ms  anon
#   undefined name or wrong IP version

@,-                         RTT-1000 ms  32768 secret1234567890
# *127.0.0.1,-
#      not answering

################
# 12/07/11 09:42:21 EET  greylist /var/dcc/map
# Re-resolve names after 11:42:21  Check RTTs after 09:57:21
# 1 total, 0 working servers
# continue not asking greylist server 32 seconds after 1 failures

@,-                         Greylist 32768 secret1234567890
# *127.0.0.1,6276
#      not answering

Apparently it can’t contact dcc1.dcc-servers.net / dcc2.dcc-servers.net / dcc3.dcc-servers.net / etc.

Running telnet dcc4.dcc-servers.net 6277 , connects me to the specified server, but running again cdcc info gives the same result as above.

To resolve this , run cdcc rtt.

Sample of output:

# cdcc rtt


# 12/07/11 09:45:42 EET  /var/dcc/map
# Re-resolve names after 11:44:50  Check RTTs after 10:00:41
# 1256.98 ms threshold, 1235.85 ms average    12 total, 11 working servers
IPv6 on   version=3

dcc1.dcc-servers.net,-      RTT+1000 ms  anon
#  200.81.186.149,-                                             SION ID 1111
#     100% of  1 requests ok  379.30+1000 ms RTT       100 ms queue wait
#  209.169.14.26,-                                     x.dcc-servers ID 104
#     100% of  1 requests ok  288.80+1000 ms RTT       100 ms queue wait
#  209.169.14.29,-                                     x.dcc-servers ID 104
#     100% of  1 requests ok  276.54+1000 ms RTT       100 ms queue wait

From the documentation
RTT [−N]

measures the round trip time to the DCC servers. It does this by discarding accumulated information and forcing a probe of all listed server IP addresses.

Beware that when run with sufficient privilege, the RTT operation is like the info and load operations and displays cleartext passwords.

−N displays the reverse DNS name of each server.

After that, running cdcc info will produce valid results and DCC will work as it should.

1 comment

  1. george

    very helpful, thank you for the info !

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