Telnet Connection Slow to Linux Server

[SpiritOfLennon]

Hi,
I have a red hat release 6.2 kernel 2.2.14 server which I am trying to connect to across a WAN using telnet. When I issue the telnet connection the connection is made after a few seconds and then the connection hangs for about a minute before a login is presented. I believe this has something to do with the server authorising the IP address of the client prior to offering a connection, how can I address this problem? Any assistance would be appreciated.
SOL
I'm only guessing but my guess work generally works for me.

 

[stanhubble]

It is most likely a problem with the DNS reverse arp lookup of your client machine by the server.

i.e. the server has the clients ip address and is trying to resolve the name of the client.

HTH
stan

 

[SpiritOfLennon]

Okay, so how can I check this and resolve the problem. Sorry to be a pain but I am fairly new to Linux. SOL
I'm only guessing but my guess work generally works for me.

 

[k6panzer]

It could help to add a host entry on the linux box for you client machine (if you are using static IPs). Also, the DNS resolve order can cause delays like this for services such as telnet and ftp.

 

[Nostradamus]

Do you get fast ping replies from the machine?
It's not just slow because your connecting over a WAN interface? How fast is your connection?

I belive however that it's something the dns and your backward resolver (hostname to ip). just as Stan suggested.

Several ftp-servers have an option to verify that a person behind a IP is really who they claim to be. By tracing the person back and try to resolve the ip to hostname. But, that demands that the dns-server is set up to resolve that. Many dns-admins forget to set up this.

run nslookup from your linux-box.
enter...

server=[ip of dns-server]
set q=PTR
[ip of linux-machine]

do you recieve any answers on that?

I suppose you can also do what k6panzer's suggests. If so try to change the resolv order. Local first (/etc/hosts) and then dns/(bind). I belive the /etc/resolv.conf contains the resolv order information. /Sören

 

[ifincham]

Hi,

Re name resolution - the file that controls the order in which various ways of resolving a host are tried is /etc/nsswitch.conf . For example an entry like :

hosts: files dns

...means use /etc/hosts first, then use dns (as per servers in /etc/resolv.conf).

Regards