Latest LQ Deal: Latest LQ Deals
Go Back > Forums > Linux Forums > Linux - Networking
User Name
Linux - Networking This forum is for any issue related to networks or networking.
Routing, network cards, OSI, etc. Anything is fair game.


  Search this Thread
Old 01-18-2018, 02:31 AM   #1
LQ Newbie
Registered: Jan 2018
Posts: 2

Rep: Reputation: Disabled
Email server problem on centos 6.x & some ports is closed


my email server does not work properly. I used 587 port for smtp.
but it does not work properly. I looked nmap sT xx
it gave 587 port is closed. I tried to open it via iptables. it does not work.

and we have fqdn problem too. it does not resolve truely. our isp
send dns request to abnormal places, namely they add extra hop points. can these ports,587 25, closed or redirected by isp? our system started to work very slowly for 1.5 months.

sometimes our connection gave retrasnmission errors. login issues occured.

any idea?
Old 01-18-2018, 07:12 AM   #2
Registered: Jun 2004
Location: Athens, Greece
Distribution: Slack@Home - RHEL@Work
Posts: 150

Rep: Reputation: 29
Your post is far from being clear but let me give it a try,
Can you telnet port 587 on you server?
Try localhost, try the lan ip and finally the external ip.
That could help narrowing down possibilities a bit


dns, isp, network

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Testing a Centos 7 Mail server using telnet response is connection closed by foreign corodo Linux - Server 1 09-22-2015 08:51 AM
Email with Postfix,Dovecot & MySQL on CentOS 5-CentOS 6 issues redhat19 Linux - Server 6 05-12-2012 10:15 AM
network problem, ports closed, TX=0 qrange Linux - Networking 3 09-17-2010 04:37 AM
Newbie DNS server & /etc/resolv.conf problem (CentOS 5.x) aspasia Linux - Newbie 0 03-24-2008 06:10 PM
Closed ports? Greg21 Linux - Networking 4 01-15-2002 12:37 AM > Forums > Linux Forums > Linux - Networking

All times are GMT -5. The time now is 08:11 PM.

Main Menu
Write for LQ is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Open Source Consulting | Domain Registration