Linux CentOS 6.3 two NIC cards don't get along

Portal Home > Knowledgebase > Articles Database > Linux CentOS 6.3 two NIC cards don't get along

Posted by Sfed, 09-29-2012, 05:01 PM
I used to have CentOS 6.2 version and everything running okay on previous server. This one doesn't want to work. I cannot get two Network Interface Cards work on same time. I have set up eth0 and eth1 Subnet, 80.79.113.1/29 IP addresses allowed 80.79.113.1 - 80.79.113.6 Subnet Mask 255.255.255.248 GateWay 80.79.113.6 # system-config-network I have here two NICS shown. dns conf, picture: https://tmpdmp.com/i/ac858a9aac226b3e/c18188d49c8c56ef eth0, picture: https://tmpdmp.com/i/782c38fcb26dc9c6/a36d5c967fd6dd07 eth1, picture: https://tmpdmp.com/i/fd8d85d0f88c35e7/0dfea4f8fe380d88 Tried, # cd /etc/udev/rules.d/ # rm -Rf 70-persistent-net.rules # reboot // # vi /etc/sysconfig/network-scripts/ifcfg-eth0 DEVICE=eth0 BOOTPROTO=none BROADCAST=80.79.113.7 IPADDR=80.79.113.2 NETMASK=255.255.255.248 ONBOOT=yes TYPE=Ethernet HWADDR=00:e0:81:b3:20:7c DNS2=80.79.18.244 DNS1=80.79.0.1 IPV6INIT=no USERCTL=no GATEWAY=80.79.113.6 # vi /etc/sysconfig/network-scripts/ifcfg-eth1 DEVICE=eth1 BOOTPROTO=none BROADCAST=80.79.113.7 IPADDR=80.79.113.3 NETMASK=255.255.255.248 ONBOOT=yes TYPE=Ethernet HWADDR=00:e0:81:b3:20:7d DNS2=80.79.18.244 DNS1=80.79.0.1 IPV6INIT=no USERCTL=no GATEWAY=80.79.113.6 I can ping them, in server itself by local. # ping 80.79.113.2 PING 80.79.113.2 (80.79.113.2) 56(84) bytes of data. 64 bytes from 80.79.113.2: icmp_seq=1 ttl=64 time=0.044 ms 64 bytes from 80.79.113.2: icmp_seq=2 ttl=64 time=0.013 ms 64 bytes from 80.79.113.2: icmp_seq=3 ttl=64 time=0.011 ms 64 bytes from 80.79.113.2: icmp_seq=4 ttl=64 time=0.012 ms PING 80.79.113.3 (80.79.113.3) 56(84) bytes of data. 64 bytes from 80.79.113.3: icmp_seq=1 ttl=64 time=0.067 ms 64 bytes from 80.79.113.3: icmp_seq=2 ttl=64 time=0.013 ms 64 bytes from 80.79.113.3: icmp_seq=3 ttl=64 time=0.012 ms 64 bytes from 80.79.113.3: icmp_seq=4 ttl=64 time=0.020 ms # ifconfig eth0 Link encap:Ethernet HWaddr 00:E0:81:B3:20:7C inet addr:80.79.113.2 Bcast:80.79.113.7 Mask:255.255.255.248 inet6 addr: fe80::2e0:81ff:feb3:207c/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:287622 errors:0 dropped:0 overruns:0 frame:0 TX packets:449849 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:25971376 (24.7 MiB) TX bytes:586193348 (559.0 MiB) Interrupt:18 Memory:dc420000-dc440000 eth1 Link encap:Ethernet HWaddr 00:E0:81:B3:20:7D inet addr:80.79.113.3 Bcast:80.79.113.7 Mask:255.255.255.248 inet6 addr: fe80::2e0:81ff:feb3:207d/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:2882 errors:0 dropped:0 overruns:0 frame:0 TX packets:64 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:221147 (215.9 KiB) TX bytes:12840 (12.5 KiB) Interrupt:19 Memory:dc460000-dc480000 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:42593 errors:0 dropped:0 overruns:0 frame:0 TX packets:42593 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:67459432 (64.3 MiB) TX bytes:67459432 (64.3 MiB) If I stop eth0 then eth1 will go instead of it online and 80.79.113.3 is reachable. When I start eth0 then 80.79.113.2 is reachable but other one not from outside world. in localhost they are both pingable
Posted by rcs, 09-29-2012, 06:40 PM
if eth0 is up then connection to that network will go from the router to that interface, since the ip 80.79.113.3 is not on that interface, it won't be reached.
Posted by Steven, 09-29-2012, 08:51 PM
It appears you need to use bonding.. http://www.how2centos.com/centos-6-channel-bonding/
Posted by Sfed, 09-30-2012, 01:59 AM
What do you mean by that? There are TWO different Network Interface Cards. ETH0 has 80.79.113.2 and ETH1 has 80.79.113.3 why doesn't ETH1 start through 80.79.113.3 and only 80.79.113.2 is online until it get's cut off NIC2 will not go online. Can you clarify what this would make better? Would two interfaces (eth0 & eth1) start using both their own network card or only one network card?
Posted by Sfed, 09-30-2012, 08:22 AM
Case solved, Thumbs Up to Steven ! Thanks mate

Add to Favourites Print this Article

Knowledgebase

Linux CentOS 6.3 two NIC cards don't get along

Our Services

Client Menu

Legal