Weird issue

[mih911]

I have msfc were I defined the different vlan under corresponding subnets. Some of the msfc interfaces has multiple subnets under one interface where as some of them same single class C subnet. The default route from msfc is pointing to core router and core router is pointing to WAN router. I have a UNIX box on other campus have full access privilege for authorize users. No access list is preventing connectivity to and from UNIX that is on other campus and connection through WAN link.

I found that the telnet connection took long time from some of the subnet where as other subnets having no problem.

Like I have subnets 100, 101, 102 and 103 under interface vlan100, subnet 105 under interface vlan105 and subnet 106 under interface vlan106 on msfc.

The access from subnet 101 and 105 is very slow mean taking long time to login request to appear where as subnet 100, 102 and 103 under interface vlan100 and subnet 106 under interface 106 have not problem.

Ping response time is same and good from all subnets and trace route is also no have any drop or time issue from any subnets.

Any one can help me in solving the issue?

[srd]

That actually sounds like a DNS issue rather than a routing or switching issue.

Make sure that all of the hosts on all of the subnets have both correct forward and correct reverse (in-addr.arpa) entries.

If it's a modern Unix system (e.g. Linux, xBSD or Solaris) it'll be trying to lookup the connecting address. This process can crawl along if the DNS is not correctly configured. In the case of most Linux and BSD distributions it will also be trying ident back to the connecting host.

[mih911]

I don't have a good understanding of DNS. The DNS entries are handle by other department.

But, I need some more clear idea of how you conclude that it is DNS issue.

If you are talking about the DNS entry of client or computer that I’m using to initiate the telnet session.

Then I like to give you the detail of test I performed.

I'm using a Win2000 machine. In that machine when I assigned a IP address of one subnet (100) every thing work fine but when I assigned a IP address of other subnet (101) telnet session took long time to login request appear.

Please, send more some more details.