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We are running RedHat Linux on two front end webservers both running Apache HTTP Server.

I have done a diff on both httpd.conf files and there are no differences but the server hostnames. We have seen some issues were one of the servers is sending a reset to the load balancer when a request is made to the 1st webserver. so I noticed somthing unique:

When I run netstat-an | grep 80 | grep LISTEN the results are different.

1st shows: LISTEN (I am used to seeing this which I believe allows any IP on server to respond over port 80.

2nd shows: :::80 LISTEN (I have never seen this before)

Can anyone explain why the 2nd webserver looks different than the first? And if this is a problem or no big deal? Thanks

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migrated from Jun 19 '12 at 4:54

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up vote 4 down vote accepted

The second :::80 is indicating that the httpd service is listening on all available addresses which includes IPv6 addresses. The former doesn't have an IPv6 address address configured so it shows which means all available IPv4 addresses.

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The first is showing that port 80 is bound on ipv4 whereas the second shows that port is bound on the ipv6 unspecified address.

I'm not certain why this would be causing issues for your load balancer however I'd check the configuration of the network interfaces if the httpd configurations are the same.


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