reverse DNS mapping? is it talktalk's fault?

rudeboymcc · 4 Apr 2007 at 17:09

Hi. I'm at bristol uni and at home in rbistol (with daemon internet) I can ssh fine into Bristol's server.

When i tried it in london (using talktlak broadband) it kept saying connection closed. I e-mailed a tutor thinking the server's had been shut down, and he said "if the connection is closed, then that is because your ISP does not
prvoide a reverse DNS mapping". This guy is really clever but before I go on and move from talktlak to demon i just wnat to check that that is the only problem that could be cuasing this.

For example i'm yusing a differnet wireless route (belkin vs netgear) and am wondering if that could be anythin to do with ti.

thanks for any help.

Tui · 4 Apr 2007 at 18:33

Looks like an initial security measure to check a "proper" incoming IP address by its reverse DNS entry.
No reason to not believe the guy, why not check with Bristol Uni Network Support?

A lot of ISPs, including Demon, do provide reverse DNS entries, even dynamic addresses will have a placeholder hostname based on the IP address, just laziness if TalkTalk don't.

oddjob62 · 4 Apr 2007 at 19:00

Tui said:
A lot of ISPs, including Demon, do provide reverse DNS entries, even dynamic addresses will have a placeholder hostname based on the IP address, just laziness if TalkTalk don't.

There's PLENTY of ISPs who don't have pointer records unless you tell them. Often it will take a while to be able to speak to someone who knows what you are talking about though

rudeboymcc · 4 Apr 2007 at 20:06

so you reckon i can call up talktalk and get them to enable it?

what exactly do i need to ask for?

HEADRAT · 4 Apr 2007 at 20:17

rudeboymcc said:
so you reckon i can call up talktalk and get them to enable it?

what exactly do i need to ask for?

LOL good luck, the average support guy wouldn't know an in.addr.arpa zonefile or PTR record if it jumped up a took a lump out of him!

HEADRAT

tolien · 4 Apr 2007 at 21:44

Easy way to find out if your Talktalk IP has a PTR record for it...find out what the IP is (www.whatismyip.com or whatever), and look it up (nslookup [IP] will do).

silversurfer · 5 Apr 2007 at 03:52

That times out for me

tolien · 5 Apr 2007 at 13:40

silversurfer said:
That times out for me

The link I gave? Works for me :confused:

It's at the top of the page at www.dnsstuff.com, you can get it from ipconfig /all or your router's status information.

matja · 5 Apr 2007 at 15:02

You may also have a PTR record which doesn't resolve back to your IP, or perhaps multiple PTR records.

It happens, I had a BT Business DSL connection once which had 2 different PTR records, one resolved back to my IP, one resolved to a different IP, so anything doing DNS checking immediately thought I was some dodgy spoofing haxor.