i can not ping 127.0.0.1, what can be the problem?

[frederick van tagero]

Dear friends,
I met one situation what has never not been, one of my server suddenly down in networking connection, and even if i restart all networking successful, i can not ping every thing at all, even if it self. no other computer can access again. I check flag in proc, icmp_echo_ignore_all is 0. I do not know what the problem is, who can help me in tips? friends.

Best Regards,
Frederick

[Balaji N · Accepted solution]

hi
a peculiar problem. just guessing.

the tcp stack is not initialised or something that like i guess. this is because, u say that u r not able to ping the local host.

can u check out /proc/net and see if anything useful is there. did u recompile your kernel recently or something like that.

can this server be restarted. if yes, can u see if it helps.


and before you do all this have a look at dmesg and /var/log/messages. hope u find some useful info there.

and pls post the results how u fixed this problem.

hth
-balaji

[frederick van tagero]

thanks for your help, i will try under your instruction, however, the result only can be post until tommorrow.

Best regards,
Frederick

[Balaji N]

ok. waiting for ur feedback.

regards
balaji

[frederick van tagero]

there are many files in /proc/net, which one could be useful?

no kernel recompile but apache recompiled before.

I restart it, caught none unnormal message, but either can not ping. where is the initial about the tcp stack?

Best Regards,
Frederick

[Balaji N]

hi
in the dmesg or in /var/adm/messages are u getting any related messages. something like this.
+++++++++++++++++++++++++++++
sudo dmesg | grep -i tcp
NET4: Linux TCP/IP 1.0 for NET4.0
IP Protocols: ICMP, UDP, TCP, IGMP
TCP: Hash tables configured (established 16384 bind 32768)
+++++++++++++++++++++++++++++++

also, forgot to ask, is some firewall running? and what does the output of ifconfig -a shows.

just guessing as i dont have any clues?
-balaji

[frederick van tagero]

dear balaji,

I use redhat, found none directory as /var/adm;

One more thing, I found suddenly it can work after I restart it again.

i do not know why, however, thanks very much to your help.

Best Regards,
Frederick

[Balaji N]

good that it works. and sorry, the directory is /var/log/messages. it was a typo.

-balaji