Symptoms
- RHEL7/CentOS 7 is used.
- Website points to correct IP address, but not accessible:
Site can't be reached
- Curl utility shows the following:
# curl -I http://example.com -v
* About to connect() to example.com port 80 ( #0 )
*Â Trying 203.0.113.2… No route to host
* couldn’t connect to host
* Closing connection #0
curl: (7) couldn’t connect to host - Traceroute utility shows the following:
# traceroute -T -p 80 example.com
traceroute to example.com (203.0.113.2), 30 hops max, 60 byte packets
1 gw4.example2.com (1.1.1.1) 0.211 ms 0.204 ms 0.250 ms
2 nsl-example3.com (2.2.2.2) 0.524 ms 0.369 ms 0.509 ms
16Â * * *
17Â * * *
18Â * * *
19Â * * web18.example4.com (3.3.3.3)Â 302.789 ms !X <——– “communication administratively prohibited” - HTTP service is not allowed on local firewall:
# firewall-cmd –list-services | grep http
#
Cause
Local firewall blocks connections to HTTP service.
Resolution
- Login to the server over SSH
- Allow HTTP service:
# firewall-cmd –permanent –add-service=http
success
# firewall-cmd –reload
success
# firewall-cmd –list-services
ssh dhcpv6-client http