I have a remote SCO 5.05 server that has several netterminals accessing with telnet just fine. I also have a new router with firewall enabled. Port 23 is routing to the SCO server and a pcanywhere port routing to a workstation.
I can connect to the workstation fine with PCAnywhere but I cannot telnet to the server successfully from outside the local network.
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I have a firwall in the router that has port 23 open and directed to the IP address of the SCO server
I also can ping the router IP address from outside.
I also have the PCAnywhere port open on the router directing to a workstation on the LAN that works fine from outside the network.
There are no other firewal components between the router and the server.
please answer all question asked so far.
1. can you reverse lookup on SCO the hosts trying to connect?
2. TCP connections are bidirectional, so you need to route in both directions.
is your firewall open in *both* directions (TCP)?
3. Are NAT or Packet Filters or IP Chains [snipped] involved???
Also: are all names listed in /etc/hosts which try to connect?
(is a variation of 1. see above)
1: It appears that no logging to the syslog, utmp, utmpx, wtmp, wtmpx is occuring when an attempt to telnet from the outside happens.
2: I do not have the option to specify the direction in the router port settings. So I can only assume that opening the port opens it in both directions.
3: The router uses NAT to redirect the packets.
All names are listed in the /etc/hosts I added the IP addresses found in the router logs for the telnet entries but it did not help.
The incomming logs in the router show the PCAnywhere and the Telnet attempts. The PCAnywhere are successful but the Telnet are not.
Since there are no log updates happening on the sco box during these attempts the telnet attemps must not be getting through the router.
assuming the name of the remote host trying to connect to SCO is: host.remote.tld
then try following:
nslookup host.remote.tld
if it does not return a IP, then your DNS failed to resolv the name/IP mapping. This may have various reasons.
If nslookup fails, try to add that name with the proper IP in /etc/hosts and try telnet again.
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by: ahoffmannPosted on 2004-02-23 at 10:40:22ID: 10434387
> .. cannot .. from outside the local network
hmm most likely a firewall or routing problem
It's hard without additional information to identify the problem.
I'd first start with routing: can you please check this out
If routing works: is there a firewall inbetween?