LinuxQuestions.org
Help answer threads with 0 replies.
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Networking
User Name
Password
Linux - Networking This forum is for any issue related to networks or networking.
Routing, network cards, OSI, etc. Anything is fair game.

Notices


Reply
  Search this Thread
Old 10-05-2017, 01:42 PM   #1
loligator
LQ Newbie
 
Registered: Oct 2017
Posts: 1

Rep: Reputation: Disabled
Issue with packets being dropped (presumably) on CentOS server with two LANS


Hello all,

Long time lurker, first time poster. Yada, yada.

I'm have a weird collection of linux skills so bear with me here. It's very possible I missed something obvious in my setup and troubleshooting.

The site in question has two physical networks, 192.168.15.0/24 and 192.168.20.0/24. These are not VLANS but two physical networks. 192.168.15.0/24 is the server network while all client machines are on the other segment.

I have a CentOS 6.9 server setup running arpwatch that has a NIC on each network. I've come to find that when I'm on a machine on the 192.168.20.0/24, I cannot SSH or connect to any other services on the arpwatch box unless I connect to it using its 192.168.20.0/24 IP address. The IP in the .15 network (192.168.15.84) is what the server's A record is pointing to and it would be nice to be able to use this to connect.

I've done packet captures and from what I can see, the syn from a .20 client is received by the CentOS server, however, it never acknowledges it. The .20 client just keeps retransmitting the syn.

iptables is not running on the server so I'm not sure what else could be causing this.

Thanks!
 
Old 10-06-2017, 03:38 PM   #2
jefro
Moderator
 
Registered: Mar 2008
Posts: 21,895

Rep: Reputation: 3616Reputation: 3616Reputation: 3616Reputation: 3616Reputation: 3616Reputation: 3616Reputation: 3616Reputation: 3616Reputation: 3616Reputation: 3616Reputation: 3616
Hello and welcome to LQ.



Unless I'm wrong /24 should force it to watch for the .20.x network only so you'd need to use a gateway to get outside of that.

Guess you could set a static arp in your 15's on that server to make it in subnet or configure gateway or fix subnet.

Again I may misunderstand the question. I don't know if your arpwatch program could fix it other than monitor.

Last edited by jefro; 10-06-2017 at 03:39 PM.
 
  


Reply


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
Bonded interface causes dropped packets in CentOS 7 PeterSteele CentOS 2 10-03-2015 06:54 PM
Is there software to find network issue? Possible packets dropped or similar issue xmrkite Linux - Software 7 03-17-2015 07:33 PM
Dropped packets Doolspin Linux - Software 1 10-22-2006 02:22 PM
too much dropped packets...Hi.. alaios Linux - Networking 2 02-10-2005 05:49 AM
packets being dropped by server from specific ip address alex_fittyfives Linux - Networking 1 08-04-2004 09:14 AM

LinuxQuestions.org > Forums > Linux Forums > Linux - Networking

All times are GMT -5. The time now is 07:07 PM.

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