Hi!
Nothing found,
root@xxxx:~# apt-get install lsof | grep :2703
root@xxxx:~# netstat -plant
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 0.0.0.0:88 0.0.0.0:* LISTEN 29298/samba
tcp 0 0 0.0.0.0:25 0.0.0.0:* LISTEN 16122/master
tcp 0 0 127.0.0.1:953 0.0.0.0:* LISTEN 9637/named
tcp 0 0 0.0.0.0:33529 0.0.0.0:* LISTEN 1149/beam.smp
tcp 0 0 0.0.0.0:538 0.0.0.0:* LISTEN 1000/gdomap
tcp 0 0 0.0.0.0:443 0.0.0.0:* LISTEN 17013/apache2
tcp 0 0 0.0.0.0:8443 0.0.0.0:* LISTEN 3210/nginx.conf
tcp 0 0 0.0.0.0:636 0.0.0.0:* LISTEN 29296/samba
tcp 0 0 0.0.0.0:445 0.0.0.0:* LISTEN 29300/smbd
tcp 0 0 0.0.0.0:4190 0.0.0.0:* LISTEN 16143/dovecot
tcp 0 0 0.0.0.0:20000 0.0.0.0:* LISTEN 25048/sogod
tcp 0 0 0.0.0.0:1024 0.0.0.0:* LISTEN 29293/samba
tcp 0 0 0.0.0.0:993 0.0.0.0:* LISTEN 16143/dovecot
tcp 0 0 0.0.0.0:995 0.0.0.0:* LISTEN 16143/dovecot
tcp 0 0 0.0.0.0:3268 0.0.0.0:* LISTEN 29296/samba
tcp 0 0 0.0.0.0:3269 0.0.0.0:* LISTEN 29296/samba
tcp 0 0 0.0.0.0:389 0.0.0.0:* LISTEN 29296/samba
tcp 0 0 0.0.0.0:135 0.0.0.0:* LISTEN 29293/samba
tcp 0 0 127.0.0.1:5000 0.0.0.0:* LISTEN 16707/python
tcp 0 0 127.0.0.1:10024 0.0.0.0:* LISTEN 3324/amavisd-new (m
tcp 0 0 127.0.0.1:10025 0.0.0.0:* LISTEN 16122/master
tcp 0 0 127.0.0.1:3306 0.0.0.0:* LISTEN 934/mysqld
tcp 0 0 0.0.0.0:587 0.0.0.0:* LISTEN 16122/master
tcp 0 0 0.0.0.0:139 0.0.0.0:* LISTEN 29300/smbd
tcp 0 0 127.0.0.1:6379 0.0.0.0:* LISTEN 1384/redis-server 1
tcp 0 0 127.0.0.1:11211 0.0.0.0:* LISTEN 1006/memcached
tcp 0 0 127.0.0.1:6380 0.0.0.0:* LISTEN 1415/redis-server 1
tcp 0 0 127.0.0.1:143 0.0.0.0:* LISTEN 16143/dovecot
tcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN 17013/apache2
tcp 0 0 0.0.0.0:464 0.0.0.0:* LISTEN 29298/samba
tcp 0 0 0.0.0.0:465 0.0.0.0:* LISTEN 16122/master
tcp 0 0 10.10.1.1:53 0.0.0.0:* LISTEN 9637/named
tcp 0 0 127.0.1.1:53 0.0.0.0:* LISTEN 9637/named
tcp 0 0 127.0.0.1:53 0.0.0.0:* LISTEN 9637/named
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 877/sshd
tcp 1 0 127.0.0.1:55315 127.0.0.1:20000 CLOSE_WAIT 25450/apache2
tcp 0 0 10.10.1.1:22 10.10.1.4:55508 ESTABLISHED 19672/sshd: user [p
tcp 0 0 127.0.0.1:11211 127.0.0.1:44658 ESTABLISHED 1006/memcached
tcp 0 0 127.0.0.1:34634 127.0.1.1:3268 ESTABLISHED 29346/sssd_be
tcp 0 0 127.0.1.1:389 127.0.0.1:57843 ESTABLISHED 29296/samba
tcp 0 0 127.0.0.1:11211 127.0.0.1:39937 ESTABLISHED 1006/memcached
tcp 1 0 127.0.0.1:50240 127.0.0.1:389 CLOSE_WAIT 23256/amavisd-new (
tcp 1 0 127.0.0.1:55296 127.0.0.1:20000 CLOSE_WAIT 25451/apache2
tcp 0 0 127.0.0.1:44658 127.0.0.1:11211 ESTABLISHED 25061/sogod
tcp 0 0 127.0.0.1:39932 127.0.0.1:11211 ESTABLISHED 16731/ocnotificatio
tcp 0 0 127.0.0.1:39937 127.0.0.1:11211 ESTABLISHED 16707/python
tcp 0 0 127.0.1.1:3268 127.0.0.1:34634 ESTABLISHED 29296/samba
tcp 0 0 127.0.0.1:11211 127.0.0.1:39932 ESTABLISHED 1006/memcached
tcp 0 0 127.0.0.1:43481 127.0.0.1:11211 ESTABLISHED 25063/sogod
tcp 0 0 127.0.0.1:47260 127.0.0.1:5672 ESTABLISHED 16731/ocnotificatio
tcp 0 0 127.0.0.1:43104 127.0.0.1:4369 ESTABLISHED 1149/beam.smp
tcp 0 0 127.0.0.1:57843 127.0.1.1:389 ESTABLISHED 29346/sssd_be
tcp 0 0 127.0.0.1:50246 127.0.0.1:389 ESTABLISHED 23894/amavisd-new (
tcp 0 0 127.0.0.1:389 127.0.0.1:50246 ESTABLISHED 29296/samba
tcp 0 0 127.0.0.1:11211 127.0.0.1:43481 ESTABLISHED 1006/memcached
tcp 1 0 127.0.0.1:55292 127.0.0.1:20000 CLOSE_WAIT 25451/apache2
tcp6 0 0 :::88 :::* LISTEN 29298/samba
tcp6 0 0 :::25 :::* LISTEN 16122/master
tcp6 0 0 :::636 :::* LISTEN 29296/samba
tcp6 0 0 :::445 :::* LISTEN 29300/smbd
tcp6 0 0 :::4190 :::* LISTEN 16143/dovecot
tcp6 0 0 :::1024 :::* LISTEN 29293/samba
tcp6 0 0 :::995 :::* LISTEN 16143/dovecot
tcp6 0 0 :::3268 :::* LISTEN 29296/samba
tcp6 0 0 :::3269 :::* LISTEN 29296/samba
tcp6 0 0 :::389 :::* LISTEN 29296/samba
tcp6 0 0 :::135 :::* LISTEN 29293/samba
tcp6 0 0 :::5672 :::* LISTEN 1149/beam.smp
tcp6 0 0 :::587 :::* LISTEN 16122/master
tcp6 0 0 :::139 :::* LISTEN 29300/smbd
tcp6 0 0 :::464 :::* LISTEN 29298/samba
tcp6 0 0 :::465 :::* LISTEN 16122/master
tcp6 0 0 :::4369 :::* LISTEN 1044/epmd
tcp6 0 0 :::22 :::* LISTEN 877/sshd
tcp6 0 0 127.0.0.1:5672 127.0.0.1:47260 ESTABLISHED 1149/beam.smp
tcp6 0 0 127.0.0.1:4369 127.0.0.1:43104 ESTABLISHED 1044/epmd
root@xxxx:~# netstat -plant | grep 2703
root@xxxx:~#
Detailing, usually I get lines like this on Sophos Network Protection log:
... Default DROP TCP 10.10.1.1 : 50263 → 208.83.137.118 : 2703 [SYN] len=60 ttl=63 tos=0x00 srcmac=52:5...
... Default DROP TCP 10.10.1.1 : 39206 → 208.83.139.205 : 2703 [SYN] len=60 ttl=63 tos=0x00 srcmac=52:5...
So, mainly this two IPs 208.83.137.118, 208.83.139.205 as destinations, not remember others.
Doing a regular WHOIS IP, seems like this IPs are for some security company, but I'm not confident with that, since no general availability for general reference for it and neither for any protocol or system related to.
Also it appears when a mail is being delivered on any direction...
I did noticed this relation to mail service since my dyndns domain was down couple of days per migration and thousands of mails from a couple of open source dev mail lists, after that the rate dropped, but if I send or receive a mail per test or coincidence...
I may being losing some functionality here... but what functionality for which any one should relay on?
Thanks!
Tomás