# Problems with Telnet **URL:** \ **Category:** Ruby\ **Created:** [January 23, 2010, 4:07pm UTC](https://www.ruby-forum.com/t/problems-with-telnet/182151 "2010-01-23T16:07:30Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![seanwarburton](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/2bfe46/32.png) [@seanwarburton](https://www.ruby-forum.com/u/seanwarburton)\ **Post date:** [January 23, 2010, 4:07pm UTC](https://www.ruby-forum.com/t/problems-with-telnet/182151/1 "2010-01-23T16:07:30Z")
Firstly I’m a total newbie not just to Ruby but programming full stop so go gentle, please 🙂 I’m looking for some help with a telnet problem. I am using a service that uses telnet to let you check the registration status of a domain name, you can only make so many requests per day so the maximum rate you can send requests at is every 200ms. You also have to keep the connection open as it takes 3 seconds to open a connection, each name has to be followed by a carriage return and new line and finally the final request needs to finish with #exit. The problem I have is this … I can open a connection no problem and if I send the following command cmd(“domain1.ca\r\ndomain2.ca\r\n#exit”) {|str| print str} I get the information I need returned for both domains but because I need to wait 200ms between each domain, I need to actually send … cmd(“domain1.ca\r\n”){|str| print str} sleep 0.2 cmd(“domain2.ca\r\n#exit”){|str| print str} When I do that I get the correct information for the first domain then it sits for a couple of seconds before returning a timed out error. Can anyone point to what I’m doing wrong and also give me some pointers on the best way to read and chomp the replies from the service. TIA Sean ---
**Author:** ![seanwarburton](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/2bfe46/32.png) [@seanwarburton](https://www.ruby-forum.com/u/seanwarburton)\ **Post date:** [January 23, 2010, 5:19pm UTC](https://www.ruby-forum.com/t/problems-with-telnet/182151/2 "2010-01-23T17:19:53Z")
Perhaps it will help if I post the actual error I receive … /usr/lib/ruby/1.8/net/telnet.rb:557:in `waitfor': timed out while waiting for more data (Timeout::Error) from /usr/lib/ruby/1.8/net/telnet.rb:692:in`cmd’ ---
**Author:** ![seanwarburton](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/2bfe46/32.png) [@seanwarburton](https://www.ruby-forum.com/u/seanwarburton)\ **Post date:** [January 26, 2010, 12:25am UTC](https://www.ruby-forum.com/t/problems-with-telnet/182151/3 "2010-01-26T00:25:43Z")
Sean W. wrote: > Firstly I’m a total newbie not just to Ruby but programming full stop so > go gentle, please 🙂 > > I’m looking for some help with a telnet problem. I am using a service > that uses telnet to let you check the registration status of a domain > name, you can only make so many requests per day so the maximum rate you > can send requests at is every 200ms. You also have to keep the > connection open as it takes 3 seconds to open a connection, each name > has to be followed by a carriage return and new line and finally the > final request needs to finish with #exit. The problem I have is this … > > I can open a connection no problem and if I send the following command > > cmd(“domain1.ca\r\ndomain2.ca\r\n#exit”) {|str| print str} > > I get the information I need returned for both domains but because I > need to wait 200ms between each domain, I need to actually send … > > cmd(“domain1.ca\r\n”){|str| print str} > sleep 0.2 > cmd(“domain2.ca\r\n#exit”){|str| print str} > > When I do that I get the correct information for the first domain then > it sits for a couple of seconds before returning a timed out error. > > Can anyone point to what I’m doing wrong and also give me some pointers > on the best way to read and chomp the replies from the service. > > TIA > > Sean Do you _have_ to wait 200ms between consecutive requests? If the ‘sleep 0.2’ is causing problems could you burst a group of requests, followed by a longer pause, followed by another grouped request eg cmd(“domain1.ca\r\n…domain5.ca\r\n#exit”) {|str| print str} sleep 1 cmd(“domain6.ca\r\n…domain10.ca\r\n#exit”) {|str| print str} etc (It’s all I can offer - like you I’m a network engineer not a programmer!) ---
**Author:** ![seanwarburton](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/2bfe46/32.png) [@seanwarburton](https://www.ruby-forum.com/u/seanwarburton)\ **Post date:** [January 26, 2010, 11:29am UTC](https://www.ruby-forum.com/t/problems-with-telnet/182151/4 "2010-01-26T11:29:39Z")
Sean W. wrote: > I can open a connection no problem and if I send the following command > > cmd(“domain1.ca\r\ndomain2.ca\r\n#exit”) {|str| print str} > > I get the information I need returned for both domains but because I > need to wait 200ms between each domain, I need to actually send … > > cmd(“domain1.ca\r\n”){|str| print str} > sleep 0.2 > cmd(“domain2.ca\r\n#exit”){|str| print str} > > When I do that I get the correct information for the first domain then > it sits for a couple of seconds before returning a timed out error. It’s waiting for a “prompt”. Having a look at the source code of Net::Telnet to see what the default is, but you can override it, either when you connect, or each time you sent a command: cmd(“String”=\>“domain1.ca\r\n”, “Match”=\>/OK\>/) What you match depends entirely on how the server implements its protocol of course, but basically you want to match whatever the sequence of characters is that says “OK, I’m done, now send me another command” If it just sends you a one-line reply then maybe you just want to match /\r\n/ This will give you a lock-step request-response. You may or may not need the 200ms sleep (maybe the server always pauses 200ms before responding?) HTH, Brian. ---
**Author:** ![seanwarburton](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/2bfe46/32.png) [@seanwarburton](https://www.ruby-forum.com/u/seanwarburton)\ **Post date:** [January 27, 2010, 2:18am UTC](https://www.ruby-forum.com/t/problems-with-telnet/182151/5 "2010-01-27T02:18:57Z")
Thanks Brian, that was it, it was waiting for a full stop! ---
**Author:** ![seanwarburton](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/2bfe46/32.png) [@seanwarburton](https://www.ruby-forum.com/u/seanwarburton)\ **Post date:** [January 27, 2010, 8:40am UTC](https://www.ruby-forum.com/t/problems-with-telnet/182151/6 "2010-01-27T08:40:49Z")
Sean W. wrote: > Thanks Brian, that was it, it was waiting for a full stop! Remember that “Match”=\>/./ means “match any single character”; “Match”=\>/./ means “match a full stop” Looking at /usr/lib/ruby/1.8/net/telnet.rb on my system, I see that the default prompt is /[$%#\>] \z/. That is, by default cmd() will collect response characters until it sees one of those four characters followed by a space and nothing else following (or until the far side disconnects, which is what was happening when you stuffed ‘exit’ into the command stream, or until a timeout occurs) I haven’t seen the protocol you’re using, but maybe it isn’t really telnet, it’s just a raw TCP socket. In that case you could use TCPSocket.open(…) and the ‘expect’ library (/usr/lib/ruby/1.8/expect.rb on my system) to wait for responses.