Hello All,

I've installed RHEL7.2 64 bit with Minimum Setting option at my server HP Proliant DL20 Gen 9 with Intel Processor and have public address and a virtual internal network.

I've done port forwarded to my server internal private IP Address to public address so that i can ssh from outside.

After fresh installation i've setup internet connection at very begnnning at the time of installation & after installation i was able to ping google.com on console and was able to ssh internally, but as soon as i tried to ssh from outside network my internet connection got lost and even after rebooting and restarting network service i tried ping google.com its says unable to resolve host.

So after looking many link for solution at web i ended up in reinstalled my Operating system and then tried ping google.com surprisingly it was working and tried again ssh internally and after that still ping google.com it was working, but as soon as i tried ssh from outside network the internet connection got lost again.

NOTE : Early i was using RHEL6 and there was no problem even after ssh from outside network it was working just fine and the reason the switch from RHEL6 to RHEL7 is docker have support for RHEL7 and above.

I've a strong feeling that something is getting updated in network script or somewhere else at my server machine.

I've disabled firewall also systemctl stop firewalld

I'm lost here, can you please help me, need assistance.

Appericate your help.

Thank You.

Regards, Amit

First thing I'd suggest is to immediately STOP what you're doing; exposing SSH externally is a hugely bad idea. You really need to use a VPN instead, rather than exposing SSH through your firewall.

Secondly, what (if any) networking/firewall hardware is between your system and the Internet? And did you re-use the RHEL 6 address on the RHEL 7 box? Same hardware? Because an ARP mismatch could cause your firewall to react to a possible MITM attack, and drop the route. Total speculation, no information to support more than a guess.

Since you're using RHEL 7, have you contact Red Hat support? You are **PAYING FOR RHEL** right?????

Hello,

First of all thanks for your prompt reply, appreciate your help.

I am stuck in here and i'm not so good in networking.

Let me explain you the whole case, earlier i was using ubuntu 16.04 Xenial LTS Server that had some problem with open ssh and was not able to ssh in LAN network from due to some problem and then i moved on to RHEL6 which worked really well and was able to ssh locally and outside. Yes i know that open ssh making it public is bad idea, then i moved to RHEL7 as docker don't have support for RHEL6 & now in RHEL7 ssh is not working well for me.

So i don't know where to stop, so my requirement is simple i want a server that support docker and i can ssh from anywhere.

can you please guide me what is the best solution for this ?

And all of this is what you posted and was understood earlier. Restating the issue doesn't provide any further information. And again, what network equipment/topology is between you and the Internet? Is this the same hardware? Providing details and answering questions is the only way anyone here can help you; if you're not going to read the replies and post answers to questions, there isn't much we'll be able to do for you. Do you have iptables rules enabled???

Again, have you contacted Red Hat support, since you are PAYING FOR RHEL, RIGHT??? There are patches for networking that you **WILL NOT** be able to get unless you're paying for RHEL. If you don't plan on paying, then you need to load the latest version of CentOS.

Or upgrade to Ubuntu 18.04 LTS. It too has 5 years of support but the actual support contract is more flexible in regards to starting and stopping.

If you are staying with RHEL (Red Hat won't support CentOS, and there are differences) then you need to contact them.

But either way, far too little information is provided about the relevant log messages or client messages at increased verbosity.

1 members found this post helpful.