The Lotus Notes Router process hangs shortly after it is started. This occurs at system start time, or if the Router is started manually with "load Router" in the console.
The Router process hangs when it tries to send an email message to a remote server. It actually hangs looking up the IP address of the remote machine.
This problem is due to bugs in glibc and the DNS resolver in Redhat (numerous versions). Redhat have some bug references related to it, most particularly 75128 (which actually talks mostly about MySQL, but also references duplicate bugs which specifically mention Lotus Notes.
There are a number of workarounds/fixes. The first is to download the fixed versions of various RPMs. The second is to add the names/IPs of the machines Lotus communicates with into /etc/hosts. There is the possibility of a DoS attack here, in that a connection not listed in the hosts file will cause the Router to hang again (easily arranged from remote location on the network).
In our environment, where direct connections to Lotus are not allowed on the affected machine, this is fine. We added the IPs of the other Notes servers that do need connectivity, and also the address of the
I'm a bit of a Notes-no-hoper, so don't trust anything I say!