Take the 2-minute tour ×
Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

I have Ubuntu box behind the router (Asus RT-N13U), port 25 is forwarded to box from router via VirtualServer feature on router.

The problem is that some clients (here host.ru) can't deliver mail to the box (example.com).

From mail.log on example.com (who receives):

timeout after DATA (0 bytes) from host.ru[77.77.77.77]

From mail.log on host.ru (sender):

to=<serafim@example.com>, relay=mx.example.com[80.80.80.80]:25, delay=12045, delays=11744/0.01/0.55/300, dsn=4.4.2, status=deferred (host mx.example.com[80.80.80.80] said: 421 4.4.2 mx.example.com Error: timeout exceeded (in reply to end of DATA command))

uname -a

Linux example 3.2.0-35-generic #55-Ubuntu SMP Wed Dec 5 17:42:16 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux

sudo tcpdump host host.ru

tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes
13:55:57.023757 IP host.ru.53602 > 192.168.1.100.smtp: Flags [S], seq 3178988342, win 5840, options [mss 1460,sackOK,TS val 111604716 ecr 0,nop,wscale 7], length 0
13:55:57.023778 IP 192.168.1.100.smtp > host.ru.53602: Flags [S.], seq 2583405147, ack 3178988343, win 14480, options [mss 1460,sackOK,TS val 280281936 ecr 111604716], length 0
13:55:57.066389 IP host.ru.53602 > 192.168.1.100.smtp: Flags [.], ack 1, win 5840, options [nop,nop,TS val 111604727 ecr 280281936], length 0
13:55:57.080032 IP 192.168.1.100.smtp > host.ru.53602: Flags [P.], seq 1:36, ack 1, win 14480, options [nop,nop,TS val 280281950 ecr 111604727], length 35
13:55:57.123961 IP host.ru.53602 > 192.168.1.100.smtp: Flags [.], ack 36, win 5840, options [nop,nop,TS val 111604741 ecr 280281950], length 0
13:55:57.123974 IP host.ru.53602 > 192.168.1.100.smtp: Flags [P.], seq 1:23, ack 36, win 5840, options [nop,nop,TS val 111604741 ecr 280281950], length 22
13:55:57.123981 IP 192.168.1.100.smtp > host.ru.53602: Flags [.], ack 23, win 14480, options [nop,nop,TS val 280281961 ecr 111604741], length 0
13:55:57.124066 IP 192.168.1.100.smtp > host.ru.53602: Flags [P.], seq 36:218, ack 23, win 14480, options [nop,nop,TS val 280281961 ecr 111604741], length 182
13:55:57.167559 IP host.ru.53602 > 192.168.1.100.smtp: Flags [P.], seq 23:142, ack 218, win 6432, options [nop,nop,TS val 111604752 ecr 280281961], length 119
13:55:57.175227 IP 192.168.1.100.smtp > host.ru.53602: Flags [P.], seq 218:283, ack 142, win 14480, options [nop,nop,TS val 280281974 ecr 111604752], length 65
13:55:57.221532 IP host.ru.53602 > 192.168.1.100.smtp: Flags [P.], seq 3038:4078, ack 283, win 6432, options [nop,nop,TS val 111604765 ecr 280281974], length 1040
13:55:57.221551 IP 192.168.1.100.smtp > host.ru.53602: Flags [.], ack 142, win 14480, options [nop,nop,TS val 280281985 ecr 111604752,nop,nop,sack 1 {3038:4078}], length 0
^C
12 packets captured
14 packets received by filter
0 packets dropped by kernel

sudo tcpdump -A host host.ru

listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes
14:20:16.612887 IP host.ru.57231 > 192.168.1.100.smtp: Flags [S], seq 1608703986, win 5840, options [mss 1460,sackOK,TS val 111969611 ecr 0,nop,wscale 7], length 0
E..<Z.@.7.{.M_^....d...._............:.........
...K........
14:20:16.612917 IP 192.168.1.100.smtp > host.ru.57231: Flags [S.], seq 1579317444, ack 1608703987, win 14480, options [mss 1460,sackOK,TS val 280646833 ecr 111969611], length 0
E..8..@.@..?...dM_^.....^"x._.....8.m..........
..T....K
14:20:16.656975 IP host.ru.57231 > 192.168.1.100.smtp: Flags [.], ack 1, win 5840, options [nop,nop,TS val 111969622 ecr 280646833], length 0
E..4Z.@.7.{.M_^....d...._...^"x.....
......
...V..T.
14:20:16.670621 IP 192.168.1.100.smtp > host.ru.57231: Flags [P.], seq 1:36, ack 1, win 14480, options [nop,nop,TS val 280646847 ecr 111969622], length 35
E..W,y@.@......dM_^.....^"x._.....8.m......
..T....V220 mx.example.com ESMTP Postfix

14:20:16.714676 IP host.ru.57231 > 192.168.1.100.smtp: Flags [.], ack 36, win 5840, options [nop,nop,TS val 111969637 ecr 280646847], length 0
E..4Z.@.7.{.M_^....d...._...^"x.....
X.....
...e..T.
14:20:16.714875 IP host.ru.57231 > 192.168.1.100.smtp: Flags [P.], seq 1:23, ack 36, win 5840, options [nop,nop,TS val 111969637 ecr 280646847], length 22
E..JZ.@.7.{qM_^....d...._...^"x............
...e..T.EHLO host.ru

14:20:16.714890 IP 192.168.1.100.smtp > host.ru.57231: Flags [.], ack 23, win 14480, options [nop,nop,TS val 280646859 ecr 111969637], length 0
E..4,z@.@......dM_^.....^"x._.. ..8.m......
..T....e
14:20:16.715010 IP 192.168.1.100.smtp > host.ru.57231: Flags [P.], seq 36:218, ack 23, win 14480, options [nop,nop,TS val 280646859 ecr 111969637], length 182
E...,{@.@......dM_^.....^"x._.. ..8.n].....
..T....e250-mx.example.com
250-PIPELINING
250-SIZE 10240000
250-VRFY
250-ETRN
250-STARTTLS
250-AUTH PLAIN LOGIN
250-AUTH=PLAIN LOGIN
250-ENHANCEDSTATUSCODES
250-8BITMIME
250 DSN

14:20:16.758845 IP host.ru.57231 > 192.168.1.100.smtp: Flags [P.], seq 23:142, ack 218, win 6432, options [nop,nop,TS val 111969648 ecr 280646859], length 119
E...Z.@.7.{.M_^....d...._.. ^"y.... %z.....
...p..T.MAIL FROM:<ri@host.ru> SIZE=3927 BODY=7BIT
RCPT TO:<serafim@example.com> ORCPT=rfc822;serafim@example.com
DATA

14:20:16.766138 IP 192.168.1.100.smtp > host.ru.57231: Flags [P.], seq 218:283, ack 142, win 14480, options [nop,nop,TS val 280646871 ecr 111969648], length 65
E..u,|@.@......dM_^.....^"y._.....8.m......
..T....p250 2.1.0 Ok
250 2.1.5 Ok
354 End data with <CR><LF>.<CR><LF>

14:20:16.812134 IP host.ru.57231 > 192.168.1.100.smtp: Flags [P.], seq 3038:4078, ack 283, win 6432, options [nop,nop,TS val 111969661 ecr 280646871], length 1040
E..DZ.@.7.wsM_^....d...._...^"y.... .......
...}..T.kNC70YzRgtGI0YPQu9C70LXRgNCwDQog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--------_next_part_10400_1819762754_11036--

.
QUIT

14:20:16.812152 IP 192.168.1.100.smtp > host.ru.57231: Flags [.], ack 142, win 14480, options [nop,nop,TS val 280646883 ecr 111969648,nop,nop,sack 1 {3038:4078}], length 0
E..@,}@.@......dM_^.....^"y._.....8.m......
..T....p...
_..._...
^C
12 packets captured
12 packets received by filter
0 packets dropped by kernel

main.cf

myhostname = mx.example.com
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
myorigin = /etc/mailname
mydestination = example.com, localhost

local_recipient_maps =

inet_interfaces = all
inet_protocols = all
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128

relayhost = 

smtpd_banner = $myhostname ESMTP $mail_name
biff = no
append_dot_mydomain = no
readme_directory = no

smtpd_use_tls=yes
smtpd_tls_cert_file = /etc/ssl/certs/smtpd.crt
smtpd_tls_key_file = /etc/ssl/private/smtpd.key
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache

mailbox_command = procmail -a "$EXTENSION"
mailbox_size_limit = 0
recipient_delimiter = +

smtpd_sasl_auth_enable = yes
smtpd_sasl_security_options = noanonymous
broken_sasl_auth_clients = yes

smtpd_delay_reject = yes
smtpd_helo_required = yes
smtpd_helo_restrictions =
    #permit_mynetworks
    permit_sasl_authenticated
    reject_non_fqdn_helo_hostname
    reject_invalid_helo_hostname
    permit

smtpd_sender_login_maps = hash:/etc/postfix/smtpd_sender_login_maps
smtpd_sender_restrictions =
    #permit_mynetworks
    reject_sender_login_mismatch
    permit_sasl_authenticated
    reject_non_fqdn_sender
    reject_unknown_sender_domain
    permit

smtpd_recipient_restrictions =
    reject_unauth_pipelining
    reject_non_fqdn_recipient
    reject_unknown_recipient_domain
    #permit_mynetworks
    permit_sasl_authenticated
    reject_unauth_destination
    #reject_rbl_client zen.spamhaus.org
    #reject_rbl_client bl.spamcop.net
    #check_policy_service unix:postgrey/socket
    permit


smtp_tls_security_level = may
smtpd_tls_security_level = may
##smtpd_tls_security_level = encrypt
smtpd_tls_auth_only = no
smtp_tls_note_starttls_offer = yes
smtpd_tls_CAfile = /etc/ssl/certs/cacert.pem
smtpd_tls_loglevel = 1
smtpd_tls_received_header = yes
smtpd_tls_session_cache_timeout = 3600s
tls_random_source = dev:/dev/urandom

master.cf

smtp      inet  n       -       -       -       -       smtpd
pickup    fifo  n       -       -       60      1       pickup
cleanup   unix  n       -       -       -       0       cleanup
qmgr      fifo  n       -       n       300     1       qmgr
tlsmgr    unix  -       -       -       1000?   1       tlsmgr
rewrite   unix  -       -       -       -       -       trivial-rewrite
bounce    unix  -       -       -       -       0       bounce
defer     unix  -       -       -       -       0       bounce
trace     unix  -       -       -       -       0       bounce
verify    unix  -       -       -       -       1       verify
flush     unix  n       -       -       1000?   0       flush
proxymap  unix  -       -       n       -       -       proxymap
proxywrite unix -       -       n       -       1       proxymap
smtp      unix  -       -       -       -       -       smtp
relay     unix  -       -       -       -       -       smtp
showq     unix  n       -       -       -       -       showq
error     unix  -       -       -       -       -       error
retry     unix  -       -       -       -       -       error
discard   unix  -       -       -       -       -       discard
local     unix  -       n       n       -       -       local
virtual   unix  -       n       n       -       -       virtual
lmtp      unix  -       -       -       -       -       lmtp
anvil     unix  -       -       -       -       1       anvil
scache    unix  -       -       -       -       1       scache
maildrop  unix  -       n       n       -       -       pipe
  flags=DRhu user=vmail argv=/usr/bin/maildrop -d ${recipient}
uucp      unix  -       n       n       -       -       pipe
  flags=Fqhu user=uucp argv=uux -r -n -z -a$sender - $nexthop!rmail ($recipient)
ifmail    unix  -       n       n       -       -       pipe
  flags=F user=ftn argv=/usr/lib/ifmail/ifmail -r $nexthop ($recipient)
bsmtp     unix  -       n       n       -       -       pipe
  flags=Fq. user=bsmtp argv=/usr/lib/bsmtp/bsmtp -t$nexthop -f$sender $recipient
scalemail-backend unix  -   n   n   -   2   pipe
  flags=R user=scalemail argv=/usr/lib/scalemail/bin/scalemail-store ${nexthop} ${user} ${extension}
mailman   unix  -       n       n       -       -       pipe
  flags=FR user=list argv=/usr/lib/mailman/bin/postfix-to-mailman.py
  ${nexthop} ${user}

Also I've set

net.ipv4.tcp_window_scaling = 0

in /etc/sysctl.conf

Could somebody help me please?

share|improve this question
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Browse other questions tagged or ask your own question.