LinuxQuestions.org
Welcome to the most active Linux Forum on the web.
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Newbie
User Name
Password
Linux - Newbie This Linux forum is for members that are new to Linux.
Just starting out and have a question? If it is not in the man pages or the how-to's this is the place!

Notices


Reply
  Search this Thread
Old 11-10-2012, 08:09 AM   #1
pankajd
Member
 
Registered: Oct 2008
Posts: 45

Rep: Reputation: 15
cent OS 6.3 : eth0 shows ip but does not ping to other machines


hi,
i have cent os 6.3 (2.6.32-279.el6.x86_64 #1 SMP), 64 bit AMD machine. It has 2 ethernet interfaces and 1 dual port ib card. initially eth0 had 192.168.16.61 as ip. we then changed it to 172.28.2.61 and ifconfig show the new ip address. Now if we try to ping any other machine of 172.28.2.0 network, it does not ping. tcpdump -i eth0 shows that it still tries to contact 16.0 network machines.
#####################
tcpdump -i eth0
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes
18:35:22.595192 IP 192.168.16.37.mdns > 224.0.0.251.mdns: 0 SRV (QM)? CanonMF4500w._http._tcp.local. (47)
18:35:22.906188 IP 192.168.16.6.mdns > 224.0.0.251.mdns: 0*- [0q] 1/0/1 (Cache flush) SRV Canonb0480b.local.:80 0 0 (89)

#####################
There is no iptables/selinux. eth1 is 172.29.2.671 which is working absolutely fine.

#ifconfig eth0

ifconfig eth0
eth0 Link encap:Ethernet HWaddr 00:25:90:58:FB:F6
inet addr:172.28.2.61 Bcast:172.28.3.255 Mask:255.255.252.0
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:109510 errors:0 dropped:0 overruns:0 frame:0
TX packets:774 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:14912536 (14.2 MiB) TX bytes:47923 (46.7 KiB)
Memory:dfd60000-dfd80000

ping 172.28.2.200
PING 172.28.2.200 (172.28.2.200) 56(84) bytes of data.
From 172.28.2.61 icmp_seq=2 Destination Host Unreachable
From 172.28.2.61 icmp_seq=3 Destination Host Unreachable

what can be the issue?

i have checked the cable and switch port, both are good.

Last edited by pankajd; 11-10-2012 at 08:17 AM.
 
Old 11-10-2012, 12:47 PM   #2
ggeminii
LQ Newbie
 
Registered: Nov 2012
Posts: 1

Rep: Reputation: Disabled
I guess your routing table is not getting updated.
Make sure "route -n" shows the right route.
If it doesn't then manually add the route so that eth0 is used for 172.28.2.0 network.
Do something like this
1.sudo route del -net 172.28.2.0 netmask 255.255.0.0
2.sudo route add -net 172.28.2.0 netmask 255.255.0.0 metric 0 dev eth0
.
I am not sure what your netmask should be.Replace it with what is right for you.Also lower metric value means higher preference for using eth0 over eth1.

Last edited by ggeminii; 11-10-2012 at 12:50 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
I cannot ping with command 'ping IP' address but can ping with 'ping IP -I eth0' sanketmlad Linux - Networking 2 07-15-2011 06:32 AM
Cent OS 2.6.9-55.0.12.ELsmp shows Kernel Panic syncing error on running tc class cba Linux - Newbie 1 01-15-2008 07:42 AM
How come I can ping between machines, but not get internet? ozymandias Linux - Networking 5 09-11-2005 05:20 PM
eth0 shows packets but cant ping LAN mikey2gorgeous Linux - Networking 12 10-05-2004 09:03 AM
Ping between machines triplem Linux - Networking 1 04-14-2003 06:17 PM


All times are GMT -5. The time now is 08:48 AM.

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
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration