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WAN ok Cannot connect over LAN?

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sts1ss
Posts: 2
Joined: 2015-11-09 17:10

WAN ok Cannot connect over LAN?

Post by sts1ss »

We have used UVNC for a long time.

Now we are finding on new PC we can connect over WAN IP, but not over LAN.

We can also connect using just a switch and no router.

We can connect to older machines. We think maybe some server setting on newer versions?

Just lost. No luck searching.
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Rudi De Vos
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Re: WAN ok Cannot connect over LAN?

Post by Rudi De Vos »

VNC setup a listener on each port he sees.
When you hover over the server icon it show the ip address(es) vnc is binded to.
(This are the ip addresses you need to use when you connect to that server)

The only restriction you can set in vnc is to allow "loopback only" , but in that case LAN and WAN would not work.

Looking at your description it looks like a routing issue.
Possible cause, just guessing as i don't have any real data, ip addresses are not he real one, but i thank you gonna understand
it better with same sample data.

PC A 192.168.1.1, 255.255.255.0
PC B 192.168.1.2
PC C 192.168.2.1
PC D 125.25.12.45 ( some internet iaddress WAN)
routerAA (192.168.2.254 (R) 192.168.1.254) connect segment 1 and 2
routerBB (192.168.1.10 (R) internet) connect segment 1 to the internet

Have you set a static routing for the 192.168.2.X else PCA try to use the default router for sending data to other segments,
including 192.168.2.X

PS: firewalls can also be set different for each network type. If it isn't a router issue it can be a firewall issue.
Some firewalls allow ports, other allow exe. If a exe (winvnc.exe) it has a different checksum, a firewall that previous
was allowing winvnc.exe could be blocked after the exe is updated.
sts1ss
Posts: 2
Joined: 2015-11-09 17:10

Re: WAN ok Cannot connect over LAN?

Post by sts1ss »

Thank you for the answer. I think I left out important detail...

We can connect to the server and log on, but over LAN we only get a blue screen, then it shuts down. Over WAN, it's fine.
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Rudi De Vos
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Re: WAN ok Cannot connect over LAN?

Post by Rudi De Vos »

When initial connection is made and then the connection is broken... 99% it is caused by a firewall ( server or viewer) site.
Does it work when you start server and viewer on the same pc and connect to localhost.
maykohli0503
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Joined: 2021-04-03 07:55
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Re: WAN ok Cannot connect over LAN?

Post by maykohli0503 »

You might be able to get a piece of your LAN software to map/forward the global IP to the RaPi’s LAN server. Can the router/modem be configured to forward the global IP when it is use on the LAN side ?
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