Router: No route is known from this host to the destination address

HCL Domino Domino Forum
1

We recently migrated to a new ISP. A company down the street happens to be using the same ISP, and so the IP addresses of our mail servers are in the same subnet.

  • our mail server: A.B.C.11

  • their mail server: A.B.C.3

When we try to send mail to them, the message eventually errors out with a “No route is known from this host to the destination address” error.

All other internal and external mail sends/receives with no problems. We only have the issue when sending to this one host. This issue did not occur with our old ISP (because out mail server was than on a different IP address).

We have Domino 6.0.1 running on RedHat 8.0.

Obviously there is some configuration issue on our side. Can anyone give me some ideas on how to troubleshoot this?

2

Subject: Router: No route is known from this host to the destination address

I’m no expert on networking but it sounds to me like your ISP is blocking you by mistake.

If you can’t telnet on port 25 from within your organization to the mail server of the company down the street, then Domino will not be able to send mail there either.

Describe the issue to your ISP.