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External hosted imap connection blocked by PlusNet?

pacem
Grafter
Posts: 175
Registered: 07-09-2007

External hosted imap connection blocked by PlusNet?

Hi all,
I have a working imap account on imap.orange.net. I know it works because:
1) I can access it from work.
2) I can access it from my home machine (on plusnet) but only if I connect to it through a tunnel to a machine not on PlusNet's network. (for those in the know I do "ssh me@another-server.com -L 143:imap.orange.net:143" and then tell my machine imap.orange.net's IP address is 127.0.0.1 before starting my email program.

I suspect PlusNet's network is causing the problem because:
1) I cannot connect normally from home (even with the firewall disabled)
2) I cannot connect if I use plusnet's cgi server as the tunnel endpoint. (e.g. ssh myaccount@ccgi.plus.net -L 143:imap.orange.net:143 and then telling my machine imap.plus.net is 127.0.0.1)

I know it is not some other home related issue because I have not trouble accessing imap.plus.net from home or work. I also have no trouble accessing imap.plus.net through a tunnel to me@another-server.com or myaccount@ccgi.plus.net) Also being able to access imap.plus.net through ccgi.plus.net but not being able to access imap.orange.net through ccgi.plus.net further suggests it is a fault with PlusNet's network.

To add further insult. When I reported the problem to PlusNet they asked for a traceroute (actually they asked for tracert but that's not possible Wink ) Traceroute only sends ICMP packets so wouldn't show if PlusNet were interfering with TCP packets on their network.

To further confuse PlusNet Customer Support imap.orange.net doesn't respond to pings so all traceroute shows is that icmp packets make it out of their network. (Well that's a supprise :twisted: )

After that PNCS refused to help; 1 reply saying "send us a traceroute" and then a refusal to help telling me to "go ask the forum".

What can I do, if PN refuse to help I will have to find another provider as I need my orange email accounts.

Does anyone have any more ideas how to find this problem or how to persuade PN to listen to me.


Paul.<><
5 REPLIES
N/A

External hosted imap connection blocked by PlusNet?

Paul,
You sound like a linux/BSD/Solaris/OS X/etc user, so one thing you could do is a tcpdump -vv port 143 and host imap.orange.net (syntax is probably wrong, but you get the idea) and get a packet dump of what is being sent and received and provide that to PlusNet.

With a bit of luck someone will know how to inteperate it Wink

Regards,
Andrew D Wiles
(FreeBSD user)
N/A

External hosted imap connection blocked by PlusNet?

PS, Welcome to the forums! Cheesy
pacem
Grafter
Posts: 175
Registered: 07-09-2007

External hosted imap connection blocked by PlusNet?

Quote
Paul,
You sound like a linux/BSD/Solaris/OS X/etc user, so one thing you could do is a tcpdump -vv port 143 and host imap.orange.net (syntax is probably wrong, but you get the idea) and get a packet dump of what is being sent and received and provide that to PlusNet.

With a bit of luck someone will know how to inteperate it Wink

Regards,
Andrew D Wiles
(FreeBSD user)


Heh, I was playing with tcpdump before you posted:

So far I've found the IMAP connection is established; I've also connected to it with "telnet imap.orange.net 143".
tcpdump -w etc shows the welcome prompt from orange, and then kmail sending my user-id and password, but no response...

I'm tempted to suspect orange but can't think why they would allow a connection at all if they were blocking on my IP address.

Grr much confusion.

Paul.<><
pacem
Grafter
Posts: 175
Registered: 07-09-2007

External hosted imap connection blocked by PlusNet?

Correction, "if they were blocking on a *range* of IP addresses" (since I can't connect through ccgi.plus.net either - it's not just my IP address with the problem.)

Paul.<><
pacem
Grafter
Posts: 175
Registered: 07-09-2007

External hosted imap connection blocked by PlusNet?

For those that are interested (I hope there is someone); here are two tcp dumps done with ethereal:

http://www.pacem.plus.com/etherdump.failing
http://www.pacem.plus.com/etherdump.working

192.168.1.100 is the machine trying to access the imap folder. It has been told imap.orange.net is 192.168.1.101 for both test. In the working test 192.168.1.101 has port 143 tunnelled to a non PlusNet server which then forwards to imap.orange.net. In the failing test the tunnel is to a PlusNet server which then forwards to imap.orange.net.

I am really pulling my hair out over this one...

Paul.<><