I have a peculiar problem with my dedicated webserver. It's running CentOS and uses PLESK for administration through web.
I noticed the problem in the title when trying to update plugins in wordpress aswell as wordpress itself. When trying to update a plugin or wordpress it throws me this error:
"Download failed.: Failed to connect to 72.233.56.139: Permission denied"
First thing I did was to apply a rule (in the PLESK firewall) that allowed both incoming and outgoing traffic to the IP, but to no avail. I further investigated this by SSHing into the server and checking the iptables, which has the following outgoing rules:
Chain OUTPUT (policy DROP)
target prot opt source destination
ACCEPT all -- 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
REJECT tcp -- 0.0.0.0/0 0.0.0.0/0 tcp flags:!0x17/0x02 reject-with tcp-reset
DROP all -- 0.0.0.0/0 0.0.0.0/0 state INVALID
ACCEPT all -- 0.0.0.0/0 0.0.0.0/0
ACCEPT udp -- 0.0.0.0/0 72.233.56.138
ACCEPT tcp -- 0.0.0.0/0 72.233.56.138
ACCEPT udp -- 0.0.0.0/0 72.233.69.88
ACCEPT udp -- 0.0.0.0/0 72.233.69.89
ACCEPT udp -- 0.0.0.0/0 66.135.58.62
ACCEPT udp -- 0.0.0.0/0 66.135.58.61
ACCEPT tcp -- 0.0.0.0/0 72.233.69.88
ACCEPT tcp -- 0.0.0.0/0 72.233.69.89
ACCEPT tcp -- 0.0.0.0/0 66.135.58.62
ACCEPT tcp -- 0.0.0.0/0 66.135.58.61
ACCEPT all -- 0.0.0.0/0 0.0.0.0/0
The other IPs are for the Akismet anti-spam filter which is also not working (it cannot connect to the akismet servers).
I contacted my host and they looked into it, but the reply I got was that they didn't know (!) what caused the problem and said I needed to figure it out myself.
First thing I tried was to stop iptables and opening up everything, but I still get permission denied on outgoing traffic (incoming is allowed and works perfectly as people can comment/spam like crazy on my blog).
Does anyone know what I could try to further troubleshoot this? It seems very strange that the traffic is still blocked even though the firewall is completely (?) shut down using "iptables stop".
Of all things, I eventually found out that the problem was caused by selinux which was set to "enforced". I changed it using
# nano -w etc/sysconfig/selinux
And changing the line "SELINUX=enforcing" to "SELINUX=permissive" and reboot my server. Now everything is working as it's supposed to.