5 thoughts on - Httpd Listening Only On IPv6 Interface On CentOS 7
Am 11.12.2014 um 04:48 schrieb Warren Young:
No, that’s just the way it is displayed for apache. In fact the service listens on IPv4 as well (given we speak about the default configuration with `Listen 80′).
Easy to verify.
Alexander
We noticed this problem when web browsers would refuse to connect to the server. *Then* we discovered the netstat oddity, and *then* we found that changing the Listen line in httpd.conf fixed it.
That leaves me still wanting an explanation for what happened.
New guess: there
As per RFC 3493 (Sections 3.7 and 5.3) an IPv6 socket will accept connections from IPv4 hosts, which will be mapped into the IPv6 address space.
I don’t have a good guess, there. If the client was actually connecting from an IPv4 address, then the IPv4 firewall rules should have applied.
At least, that’s what my testing indicates.
What I can say for sure is that a CentOS 7 system will accept IPv4 http connections if the IPv4 firewall allows that port, or if the firewall is disabled. Whatever problem you faced was caused by post-install configuration. Try making your standard changes incrementally and testing as you go until you can locate the steps where the problem occurs.
was the fix the config change or restarting of the service?
did netstat show client connections to port 80 in other states(FIN_WAIT/etc)?
high load apache websites can often run out of connections due to the limits in httpd.conf “” section. these limits can be increased if clients can no longer connect due to http child processes being stuck in other tcp states.
I’m going to need to see this happen on the next server build to test for such details.
5 thoughts on - Httpd Listening Only On IPv6 Interface On CentOS 7
Am 11.12.2014 um 04:48 schrieb Warren Young:
No, that’s just the way it is displayed for apache. In fact the service listens on IPv4 as well (given we speak about the default configuration with `Listen 80′).
Easy to verify.
Alexander
We noticed this problem when web browsers would refuse to connect to the server. *Then* we discovered the netstat oddity, and *then* we found that changing the Listen line in httpd.conf fixed it.
That leaves me still wanting an explanation for what happened.
New guess: there
As per RFC 3493 (Sections 3.7 and 5.3) an IPv6 socket will accept connections from IPv4 hosts, which will be mapped into the IPv6 address space.
I don’t have a good guess, there. If the client was actually connecting from an IPv4 address, then the IPv4 firewall rules should have applied.
At least, that’s what my testing indicates.
What I can say for sure is that a CentOS 7 system will accept IPv4 http connections if the IPv4 firewall allows that port, or if the firewall is disabled. Whatever problem you faced was caused by post-install configuration. Try making your standard changes incrementally and testing as you go until you can locate the steps where the problem occurs.
was the fix the config change or restarting of the service?” section. these limits can be increased if clients can no longer connect due to http child processes being stuck in other tcp states.
did netstat show client connections to port 80 in other states(FIN_WAIT/etc)?
high load apache websites can often run out of connections due to the limits in httpd.conf “
I’m going to need to see this happen on the next server build to test for such details.
The only reason I restarted it is because that