UDP Ports not opening?

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UDP Ports not opening?

Hi, I'm trying to get VPN working on OSX Server 10.5.7. The server's set up as OD Master.

I'm pretty sure I've got VPN set up properly from the server side (through Server Admin) and can successfully log on locally on our internal network. The problem I've got is that I can't get on from outside the office through our external ip.

I've got our router set up to port forward 500, 1701, 1723 and 4500 on both UDP and TCP but having run a few port tests online I can only get through to 1723.

I decided to check this locally first and have tried:

1. A local port scan through Network Utility - shows only 1723 open on TCP (out of those above)

2. Running a telnet (to my local network) through terminal gives me:

telnet 192.168.x.x 500 - denied
telnet 192.168.x.x 1701 - denied
telnet 192.168.x.x 1723 - allowed
telnet 192.168.x.x 4500 - denied

(same results if I use the external ip.)

It seems to me that the UDP ports are not listening and at the moment I don't think I can blame the router.

I've got the firewall off while I test this. Is there something obvious I'm missing?

Thanks.

Mac Book Pro, Mac OS X (10.5.7)

Posted on May 27, 2009 5:26 AM

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Answer 1

Camelot

Level 9

58,455 points

May 28, 2009 8:48 AM in response to Haich11

2. Running a telnet (to my local network) through terminal gives me:

This is not a valid test. Telnet attempts to connect to a TCP port, not a UDP port therefore you shouldn't expect these connections to work, even in a perfect setup.

What does a netstat show?

netstat -an | grep udp4

That will tell you whether the machine is listening to those ports. However, I suspect that is not your problem - since you can connect internally it seems clear that the VPN is working, it's the external access that isn't.

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Answer 2

Haich11 Author

Level 1

0 points

May 28, 2009 9:07 AM in response to Haich11

Thanks for the response and excuse my slight ignorance on this. New to osx server.

So here's what I get back from netstat (I've put the x's in)

Not sure what this tells me??

udp4 0 0 *.631 .
udp4 0 0 *.918 .
udp4 0 0 *.936 .
udp4 0 0 *.6970 .
udp4 0 0 *.626 .
udp4 0 0 192.168.x.x.138 .
udp4 0 0 192.168.x.x.137 .
udp4 0 0 *.138 .
udp4 0 0 *.137 .
udp4 0 0 *.49166 .
udp4 0 0 192.168.x.x.49165 .
udp4 0 0 . .
udp4 0 0 *.3283 .
udp4 0 0 *.50002 .
udp4 0 0 *.50001 .
udp4 0 0 . .
udp4 0 0 192.168.x.x.88 .
udp4 0 0 *.3659 .
udp4 0 0 . .
udp4 0 0 192.168.x.x.123 .
udp4 0 0 127.0.0.1.123 .
udp4 0 0 *.123 .
udp4 0 0 . .
udp4 0 0 192.168.x.x.4500 .
udp4 0 0 192.168.x.x.500 .
udp4 0 0 192.168.x.x.53 .
udp4 0 0 127.0.0.1.53 .
udp4 0 0 *.464 .
udp4 0 0 *.62666 .
udp4 0 0 *.53695 .
udp4 0 0 *.62283 .
udp4 0 0 *.56126 .
udp4 0 0 *.62597 .
udp4 0 0 *.58320 .
udp4 0 0 127.0.0.1.4500 .
udp4 0 0 127.0.0.1.500 .
udp4 0 0 *.1701 .
udp4 0 0 *.960 .
udp4 0 0 *.989 .
udp4 0 0 *.1007 .
udp4 0 0 *.1018 .
udp4 0 0 *.111 .
udp4 0 0 *.2049 .
udp4 0 0 *.1023 .
udp4 0 0 . .
udp4 0 0 *.5353 .
udp4 0 0 127.0.0.1.60762 .

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Answer 3

Haich11 Author

Level 1

0 points

May 28, 2009 9:12 AM in response to Haich11

p.s. just turned VPN off in Server Admin and ran the netstat again. Looks the same/similar except no 1701.

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