services question

[navin]

How should i know if the port is blocked in a HPUX server and how should i open a particular port
Thanks ,appreciated

[Sandman!]

Only firewalls can open or block ports. On HPUX servers a port is in use or not depending on whetehr a server is up and using it. lsof can tell you whether a service is bound to a particular port or not.

[navin]

can you please lil bit more specific about the command to test if th eport is in use- i normally go with netstat or grep port number from services - have not heard anyuthing about lsof
Thanks

[Sandman!]

If you have lsof then the following command will determine if a particular port say 512 is in use or not. You can get lsof from HP's Porting and Archive site http://hpux.cs.utah.edu and use it as:

# lsof -i:512
or
# netstat -an | awk 'z[split($4,z,".")]==512'

[skt_skt]

"whereis lsof" and confirm if you have that

lsof >lsof.out

lsof -i tcp >lsof_tcp.out
lsof -i udp >lsof_udp.out

[Ralph Grothe · Accepted solution]

Unfortunately, HP-UX doesn't ship lsof.
But you can stick with netstat for looking up ports currently in use on the server. (Sandmam!'s netstat line is pretty nifty as it reuses the returned last index of awk's split in situ, which is the position where the local socket's port is found; note Linux's netstat uses ":" as port separator).
However, you usually want to connect to a port from another host on whose route some packet filter may block the port.
For this to check you can use a port scanner like nmap (also not part of the standard hpux toolset) from this host.
You can get it from here
http://insecure.org/nmap/
But read the docs before using it because you may trigger off some alert with network or firewall intrusion detectors or arouse their admins' disdain.