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hcg100

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Cannot Ping Mail server IP address


I wonder if you might have an answer for me on this question.  
 
I can ping the IP address of our mail server from my laptop no problems.  However I can't ping our mail server IP address from our server which is in a data centre. This is strange because I can ping other IP's from that server that is in the datacentre, I can also ping domain names like www.google.com from it.
Any ideas on what the problem might be?  The firewall has ports 25 and 110 open.  The mail server is outside the datacentre too.

thanks
Harold
 
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oriziv
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Since you have a fire-wall, The first thing I would have check is that the fire wall doesn't block ICMP (the protocol which ping uses)
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hcg100

ASKER

It is not the firewall, because I can ping other external IP addresses and domains with no problem from the server.
1. Make sure there's no specific rule blocking ICMP to this server.
2. Make sure there's no local fire-wall on the mail server that blocks ICMP
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Once again, it is nothing on the mail server either, as I can ping that successfully from other locations, outside the data centre.  Try pinging 202.174.104.20.  
When I am logged onto the server in the datacentre I can ping sites like www.google.com but I can't ping the IP address above.
Thanks
Hi,

Since IP 202.174.104.20 is generally responding to ping, there's something on your network infrastructures that blocks ICMP.
Run tracert -d 202.174.104.20 from your server command line console. this should give you a list of hops. one of these hops blocks your ping.
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Hi
Interesting - tracert shows timeouts as the message enters the data centre where the mailserver is (which is another city actually).  This is at the 11th hop.

I have actually overcome the issue by installing a mail server on our service in our datacentre. So its a bit of a moot point, but i would still like to understand what was happenning!

thanks
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oriziv
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If ICMP is blocked, it will stop your ping.

You can try telneting to port 25 of the SMTP mail server.
If you get a connection the server is available.
If not your probably not getting mail.
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It turns out the mail server provider had blocked our server IP address for some reason.
Thanks