DCC suddenly fails on several servers

Dustin Puryear dpuryear@usa.net
Fri Oct 15 16:04:35 UTC 2004


Hi, we have several servers running DCC and we have recently begun having
problems. Here is what happened:

We had a small problem with a change that affected system IP addresses and
DNS (/etc/resolv.conf). We fixed those problems. All servers again have the
same information that they had previously. DCC then stopped working:

# cdcc info
# 10/15/04 09:33:43 CDT  /var/dcc/map
# Re-resolve names after 11:33:36
# 1 total, 0 working servers
# skipping asking DCC server 1 seconds more
IPv6 off

dcc1.dcc-servers.net,-      RTT+0 ms    anon
#   UNDEFINED

dcc2.dcc-servers.net,-      RTT+0 ms    anon
#   UNDEFINED
...

It was working fine before. Okay, so I looked at /var/dcc and found that
/var/dcc/map had changed. Does this happen automatically every day? It
appears so. Anyway, after some reading of manpages I decided to run 'cdcc
"load map.txt"':

# cd /var/dcc && cdcc "load map.txt"

This worked, as you can see below:

# cdcc info
# 10/15/04 09:34:39 CDT  /var/dcc/map
# Re-resolve names after 11:34:31  Check RTTs after 09:49:39
# 166.12 ms threshold, 189.06 ms average    12 total, 11 working servers
IPv6 off

dcc1.dcc-servers.net,-      RTT+0 ms    anon
#   142.27.70.214,-                                  CollegeOfNewCaledonia
ID 1189
#     100% of  1 requests ok  205.73+0 ms RTT          103 ms queue wait
#   194.109.153.82,-                                             NIET ID
1080
#     100% of  1 requests ok  600.30+0 ms RTT          326 ms queue wait
#   205.166.61.174,-                                                  ID
1074
#     100% of  1 requests ok  183.46+0 ms RTT          111 ms queue wait

dcc2.dcc-servers.net,-      RTT+0 ms    anon
#   132.206.27.31,-                                        dcc3mcgill ID
1275
#     100% of  1 requests ok  223.87+0 ms RTT          104 ms queue wait
#   194.119.212.5,-                                                   ID
1182
#     100% of  1 requests ok  307.92+0 ms RTT           74 ms queue wait
...

Well, it worked for a while at least. The next day /var/dcc/map has changed
again and DCC again fails.

I did a strings on /var/dcc/map and found that the working version had more
information than the non-working version:

Working /var/dcc/map:

# strings map
DCC client mapped data version #8
dcc1.dcc-servers.net
dcc2.dcc-servers.net
dcc3.dcc-servers.net
dcc4.dcc-servers.net
dcc5.dcc-servers.net
127.0.0.1
1874805073x1005
sgs_public_dcc_server
MessageCare
WEiAPG
sonic.net
neonova
SINECTIS
dcc.uncw.edu
dmv.com
127.0.0.1
1874805073x1005

Non-working /var/dcc/map on the same server before I ran "load map.txt":
strings map
DCC client mapped data version #8
dcc1.dcc-servers.net
dcc2.dcc-servers.net
dcc3.dcc-servers.net
dcc4.dcc-servers.net
dcc5.dcc-servers.net
127.0.0.1
1874805073x1005
127.0.0.1
1874805073x1005

I am not familiar with the function of /var/dcc/map to know what this
actually means, but I have a feeling it is related.

Any ideas?




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