# TightVNC blocked by external firewall



## newhouse1390 (Jan 10, 2005)

I bring my laptop home with me and when I establish a VPN connection and try to launch VNC to meet up with my desktop the connection never goes. However is does work for other PC's in the building.

I can launch fine when I am at the office.

This worked at a hotel this past weekend which makes me think this is a firewall issue on my home router. Is that possible?


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## johnwill (Sep 26, 2002)

Actually, since it goes through the same router to different machines in the office, I'd think the firewall blocking it is on that end.


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## newhouse1390 (Jan 10, 2005)

If that is the case how can we explain that it worked at the hotel?


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## johnwill (Sep 26, 2002)

Well... we can't explain that. :grin:

Perhaps something changed at the office in the interim. The only thing I can see on your end is a firewall blocking outgoing requests on the machine. Am I correct that you say that you can access other machines on the office network from home using the VPN? That seems to suggest that the VPN works, and I can't imagine the router even knowing what you're doing in the VPN tunnel once it's established.


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## newhouse1390 (Jan 10, 2005)

When I plug directly into the modem (bypassing the routers) the VNC session launches successfully.

This has to be either a router issue or an issue with my home network's AD setup which uses DHCP / WINS / DNS .

I think it is because these services are going through the local domain server (@ home). 

What do you think?


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## newhouse1390 (Jan 10, 2005)

My desktop computer is not able to be pinged when I am connected behind my router at home.


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## johnwill (Sep 26, 2002)

OK, now we're making progress. How about the make/model of the router? Are you sure it provides for VPN pass-through? The fact that you can't ping is most likely simply because the router is not configured to respond to ICMP (PING) requests.


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## newhouse1390 (Jan 10, 2005)

I am able to connect to the VPN server at the office and all of my regular applications work (e-mail, internet) but I cannot launch the VNC session.

Router is a Linksys BEFW11S4 (wireless B).

I have two routers 

DI-624 
Linksys BEFW11S4

D-link router is connected to the internet and then is connected to the linsys router via a network cross cable.

Both routers have DHCP disabled and the DHCP server for the network is on the Server.

The reason the network cross is in place is because the DI-624 could not hold a reliable VPN connection, the linksys did, so I connect my work laptop wirelessly to the linksys (802.11b) router and launch my VPN connection.

I will now look in the Linksys for the ICMP ping setting.


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## johnwill (Sep 26, 2002)

Don't know why VNC doesn't work, perhaps there's some restriction on the VPN that is blocking it?


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