I try to open port 81 as a virtualhost. after setting apache, I can CURL localhost:81 from local machine and get response(yes it was listening port 81). However, when visit the same address from remote browser, browser always show TIME OUT error. I thought it might be due to firewall or selinux, so I disable both of them and try again but still failed. The commands I used to disable selinux and firewall are as below:to disable selinux:open /etc/selinux/config and change SELINUX=disabled and then reboot. I use sestatus command to check and output shows it was disabled.to close iptables:service iptables stopchkconfig iptables offand I close ip6tables either:service ip6tables stopchkconfig ip6tables offI am using CentOS 6.3. Are there other security issues besides selinux and iptables that I didn't notice? Add more informationI use IP address directly, like 123.123.123.123:81. I don't think it is due to apache conf since I can get response from local server machine through both  curl locahlost:81 and curl 123.123.123.123:81.Netstat resultafter running netstat command, I got the tcp        0      0 :::80                       :::*                        LISTEN      1809/httpd          tcp        0      0 :::81                       :::*                        LISTEN      1809/httpd  seems both 80 and 81 are working.Ifconfighere is the ifconfig -a result:eth0  Link encap:Ethernet  HWaddr 00:50:56:9B:24:D6        inet addr:101.251.235.162  Bcast:101.251.235.163  Mask:255.255.255.252      inet6 addr: fe80::250:56ff:fe9b:24d6/64 Scope:Link      UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1      RX packets:16046 errors:0 dropped:0 overruns:0 frame:0      TX packets:15092 errors:0 dropped:0 overruns:0 carrier:0      collisions:0 txqueuelen:1000       RX bytes:3370807 (3.2 MiB)  TX bytes:2352380 (2.2 MiB)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:65536  Metric:1      RX packets:70 errors:0 dropped:0 overruns:0 frame:0      TX packets:70 errors:0 dropped:0 overruns:0 carrier:0      collisions:0 txqueuelen:0       RX bytes:19119 (18.6 KiB)  TX bytes:19119 (18.6 KiB)
no iptables, no selinux, port 81 in virtualhost still not working
centos;apache httpd;apache virtualhost