VPN connection using DSL

Question

VPN connection using DSL

Guest (visitor)

(OP)

25 Mar 01 23:11

I've successfully configured the client VPN setup to connect to my company's LAN from home using a dial-up connection. I got a DSL connection yesterday, and the VPN doesn't work when connected on the DSL. Please help me get the VPN working over the DSL.

Thanks in advance!

jeter (TechnicalUser) · Answer 1 · 2001-03-26 00:37:11

If this is a DSL modem there should not be any trouble in setting up VPN. Now on the other hand if this is a router than your going to have trouble. The only vpn I have seen work ( not saying there are not others ) is Cisco VPN 3000.

J.Fisher CCNA
Jeter@LasVegas.com

LordCisco (MIS) · Answer 2 · 2001-03-26 16:53:08

The problem here is"PROBABLY"the MTU at which the networks are trying to communicate heheheheh youd first test the situation by pinging the vpn # how many go through ne that dont
then ping with a small MTU then medium MTU then a large MTU till one of the 3 gets you 100% sucessfull responces ummm well now you know the MTU to use heheh next where to put that darn MTU ;) thats ur job if you get this far let me know ;) if your reading this thread and know what im talking about (maby the cisco 3000 guy)u can continue the explination if not ill continue good luck
Lordcisco.com A+,MCP,MCSE,CCNA,CCDA,(do brainbench certifications count)

billhome (IS/IT--Management) · Answer 3 · 2001-03-26 21:58:46

Yeah, PPPOE problems, LC may be right.  There may be of other factors that are present as well.

First, does the ISP support a IPsec?  Does the router you have support IPsec?  I know a Linksys router is IPsec compliant, but the numbers so far of the types of routers that are IPsec compliant are somewhat low.  Although, with large increase in such connection types as *DSL and cable, and the RFCs regarding IPsec standardization, the number of IPsec compatible routers will probably increase.

The nest question you may ask is are you using PPPOE as LC mentioned above?  PPPOE will fragement packets and the frame size it uses is less than current standards.  I think something like,  around, I'm not really sure, 80 bits or so.  That can have an effect of shutting you down as well. That information can be found by doing a search for PPPOE on net.

Basics, from what I understand is:
In order to be IPsec compliant,your client will have to make a connection to the gateway on 500/UDP.  That is where you "key" is made.  Then the client must be able to communicate with IP type 50/51( ESP and/or AH)over the wire.

Just some guesses and musings!  At the end of the day all that really matters is was it fun!

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VPN connection using DSL