Help with /etc/services

UNIX AIX
1

Hi
In my AIX 5.3 box I already have the below entry:

#cat /etc/services | grep -i 3602
infiniswitchcl  3602/tcp                # InfiniSwitch Mgr Client
infiniswitchcl  3602/udp                # InfiniSwitch Mgr Client

Now I got an requirement to add the below entry in the same port number 3602.

sapmsDSM        3602/tcp        # SAP Sol Mon System Messaging Service Port

Can I do that or will it impact anything ?

Please assist

2

If there is not already a service running at this port, you will have no problem. You can check with netstat -an| grep "\.3602" if one is currently up. But usually the /etc/services is just prepared with entries for well known ports.

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3

Just follow what Zaxxon stated.

Just for info (because it is not relevant in your case), but in some very special case, you may want to add aliases into /etc/services , this could be done entering entries this way.

infiniswitchcl  3602/tcp sapmsDSM

(i used such kind of notation once, many years ago and that was on an HP-UX system (or maybe solaris ... i'm not sure) , not sure how the other OS handle it)

... and for sure the /etc/services were initially not designed in that purpose.

4

There is a pre-requisite for running SAP that you need to disable a large number of ports in the /etc/services file before installing the SAP application.

Services 32xx, 33xx 36xx 48xx need to be removed.

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5

I'm not sure if you, ross, meant it that way, but i would like to point out the following for clarification: the file /etc/services is just a translation device for port names to port numbers, similar to the /etc/hosts file, which translates host names to IP addresses. Its content is mostly derived from RFC1700.

Removing an entry there will in no way close or disable a certain port, just like removing an entry from /etc/hosts will not prevent communiaction with the mentioned host.

To disable communication via a certain port one will have to resort to some layer-4 filtering, i.e. firewalling: IPSec, iptables or something such.

I hope this helps.

bakunin

6

you can do it. it will not harm anything. /etc/services is just a file to map ports/service names/protocols.

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7

it will not effect any other services.you can proceed .

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