defining DNS on a 3550 switch

[rezaalikhani]

I have three 3550 switches and want to define a DNS server on one of my switches (172.16.2.10). I have done the following in the DNS switch:

3550(config)#ip domain-lookup

3550(config)#ip host Setad 172.16.8.2

3550(config)#ip host MAVAD 172.16.5.2

3550(config)#ip domain-name cressnet.com

****************************************

I have done the following on the 172.16.5.2 (MAVAD) switch (one that is not a DNS):

3550(config)#ip domain-lookup

3550(config)#ip name-server 172.16.2.10

3550(config)#ip domain-name cressnet.com

****************************************

In normal operation I can telnet from 172.16.5.2 to 172.16.8.2; but in this situation, when I issue the "Setad" to telnet Setad (172.16.8.2) from the 172.16.5.2, nothing happens.

Please help!

Thanks.

[lgijssel]

You may not have understood the function of the commands that you entered. Please review the following URL for a description of DNS support in the IOS:

http://www.cisco.com/en/US/tech/tk648/tk362/technologies_tech_note09186a00800c525f.shtml#topic1

Regards,

Leo

[rezaalikhani]

Thanks for your reply.

My DNS server switch hostname is "MUT-FIBER-SWITCH" and its IP address is 172.16.2.10. Look at the DNS configuration in this switch:

MUT-FIBER-SWITCH#sh hosts

Default domain is not set

Name/address lookup uses domain service

Name servers are 255.255.255.255

Host Port Flags Age Type Address(es)

Setad None (perm, OK) 44 IP 172.16.8.2

MAVAD None (perm, OK) 0 IP 172.16.5.2

*****************************************************

I have set the following configuration in the MAVAD switch:

MAVAD(config)#ip domain-lookup

MAVAD(config)#ip name-server 172.16.2.10

and

MAVAD:#ping 172.16.2.10

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 172.16.2.10, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms

and

MAVAD:#ping 172.16.8.2

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 172.16.8.2, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/4 ms

and

MAVAD:#telnet 172.16.8.2

Trying 172.16.8.2 ... Open

Welcome To Master Switch In SETAD

Username: Malek

Password:

SETAD>exit

but

MAVAD:#Setad

Translating "Setad"...domain server (172.16.2.10)

% Unknown command or computer name, or unable to find computer address

and

MAVAD:#ping setad

Translating "setad"...domain server (172.16.2.10)

% Unrecognized host or address, or protocol not running.

[mheusinger]

Hello,

as already pointed out in a previous post the 3550 will not operate as a DNS server. The commands you gave on your "DNS switch" will only be used locally. There will be no response to DNS requests though.

So to have the possibility to use names instead of ip addresses you need to specify "ip host ..." commands on all your switches or setup a real DNS server.

Hope this helps! Please rate all posts.

Regards, Martin

[rezaalikhani]

thanks;

How can I setup a real DNS server on 3550?

[lgijssel]

Terribly sorry but you can't. There is no support for this in the IOS. You will have to revert to a unix or windows dns server.

Regards,

Leo

[rezaalikhani]

Ok, interesting!

So the DNS commands in the 3550?????

I don't understand.