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Hi all, <br>
I'm pulling my hair out on this problem and wanted to throw it out
there to see if anyone else had run across it. <br>
<br>
I recently restarted my server. There were some network config issues
that caused the interfaces not to come back up, but my colo company got
those resolved. <br>
<br>
However, after restart, my IMAPS server has stopped responding to
outside requests. I can successfully access IMAP from localhost, as
well as via SSH tunnelling, so I know it is working. <br>
<br>
I've tried all sorts of "listen=" configurations, and checked lsof
& tcpdump to rule out other problems, but it just seems as though
dovecot isn't responding. <br>
<br>
TCPDUMP (notice the TCP SYN but no response):<br>
<tt>/var/log 89# tcpdump -vvs 192 port 993<br>
tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size
192 bytes<br>
17:37:54.101518 IP (tos 0x0, ttl 112, id 56543, offset 0, flags [DF],
length: 48) c-24-9-151-115.hsd1.co.comcast.net.3132 >
mail.server.com.imaps: S [tcp sum ok] 1828791628:1828791628(0) win
16384 <mss 1460,nop,nop,sackOK><br>
17:37:58.282840 IP (tos 0x0, ttl 59, id 54721, offset 0, flags [DF],
length: 60) dsl001-148-165.sfo1.dsl.speakeasy.net.39250 >
mail.server.com.imaps: S [tcp sum ok] 3827175783:3827175783(0) win 5840
<mss 1460,sackOK,timestamp 1555809446 0,nop,wscale 2><br>
17:38:00.130267 IP (tos 0x0, ttl 112, id 56548, offset 0, flags [DF],
length: 48) c-24-9-151-115.hsd1.co.comcast.net.3132 >
mail.server.com.imaps: S [tcp sum ok] 1828791628:1828791628(0) win
16384 <mss 1460,nop,nop,sackOK><br>
17:38:01.283013 IP (tos 0x0, ttl 59, id 54722, offset 0, flags [DF],
length: 60) dsl001-148-165.sfo1.dsl.speakeasy.net.39250 >
mail.server.com.imaps: S [tcp sum ok] 3827175783:3827175783(0) win 5840
<mss 1460,sackOK,timestamp 1555810196 0,nop,wscale 2></tt><br>
<br>
LSOF:<br>
<tt>/var/log 91# lsof -i | grep imap<br>
sshd 4475 andrew 11u IPv4 39601 TCP
localhost:34661->localhost:imaps (ESTABLISHED)<br>
dovecot 6540 root 5u IPv4 38988 TCP *:imaps (LISTEN)<br>
imap-logi 6599 dovecot 9u IPv4 39602 TCP
localhost:imaps->localhost:34661 (ESTABLISHED)<br>
imap-logi 6629 dovecot 1u IPv4 38988 TCP *:imaps (LISTEN)<br>
imap-logi 6630 dovecot 1u IPv4 38988 TCP *:imaps (LISTEN)</tt><br>
<br>
<br>
NETSTAT:<br>
<tt>/var/log 92# netstat -an | grep 993<br>
tcp 0 0 0.0.0.0:993 0.0.0.0:*
LISTEN<br>
tcp 0 0 127.0.0.1:993 127.0.0.1:34661
ESTABLISHED<br>
tcp 0 0 127.0.0.1:34661 127.0.0.1:993
ESTABLISHED</tt><br>
<br>
STRACE:<br>
<tt>17:00:33.225030 gettimeofday({1171501233, 225048}, {480, 0}) = 0<br>
17:00:33.225072 gettimeofday({1171501233, 225090}, NULL) = 0<br>
17:00:33.225113 poll([{fd=7,
events=POLLIN|POLLPRI|POLLERR|POLLHUP|POLLNVAL}, {fd=10,
events=POLLIN|POLLPRI|POLLERR|POLLHUP|POLLNVAL}, {fd=3,
events=POLLIN|POLLPRI|POLLERR|POLLHUP|POLLNVAL}, {fd=1,
events=POLLIN|POLLPRI|POLLERR|POLLHUP|POLLNVAL}], 4, 0) = 0<br>
17:00:33.225163 gettimeofday({1171501233, 225182}, {480, 0}) = 0<br>
17:00:33.225212 gettimeofday({1171501233, 225230}, NULL) = 0<br>
17:00:33.225260 poll([{fd=7,
events=POLLIN|POLLPRI|POLLERR|POLLHUP|POLLNVAL}, {fd=10,
events=POLLIN|POLLPRI|POLLERR|POLLHUP|POLLNVAL}, {fd=3,
events=POLLIN|POLLPRI|POLLERR|POLLHUP|POLLNVAL}, {fd=1,
events=POLLIN|POLLPRI|POLLERR|POLLHUP|POLLNVAL}], 4, 999) = 0<br>
17:00:34.225145 gettimeofday({1171501234, 225179}, {480, 0}) = 0<br>
17:00:34.225204 gettimeofday({1171501234, 225222}, NULL) = 0<br>
17:00:34.225246 poll([{fd=7,
events=POLLIN|POLLPRI|POLLERR|POLLHUP|POLLNVAL}, {fd=10,
events=POLLIN|POLLPRI|POLLERR|POLLHUP|POLLNVAL}, {fd=3,
events=POLLIN|POLLPRI|POLLERR|POLLHUP|POLLNVAL}, {fd=1,
events=POLLIN|POLLPRI|POLLERR|POLLHUP|POLLNVAL}], 4, 0) = 0<br>
17:00:34.225297 gettimeofday({1171501234, 225315}, {480, 0}) = 0</tt><br>
<br>
<br>
Has anyone seen this behavior? What's the obvious thing I'm missing
here? My host has some weird VLAN thing installed by the colo company
so I have IP aliases, but given I'm not even seeing a response to the
SYN, it doesn't seem to be a routing issue, and I can connect to my
local interface on port 993 (NOT localhost) without problems. <br>
<br>
Suggestions much appreciated, I'm stuck. I'm sure this is something
obvious and simple, but I'm looking past it right now. <br>
<br>
Andrew<br>
<br>
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Email: <a target="sig_newwin" href="mailto:andrew@50degreescorp.com">andrew@50degreescorp.com</a><br>
<br>
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