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Community Member

VPN tunnel cannot route one destination/ports more then a minute

Dear All,

I had recently established VPN tunnel from Cisco 2800 series router to VPN concentarator , this is simple a LAN to LAN VPN tunnel and i can access servers through the VPN far so good but i am facing issue with one destination/servers which is hosted on https.I can access this destination through VPN tunnel but with in minute i loose it(but other servers works

it means the VPN tunnel is not down) and if i reaaplied VPN tunnel ( remove crypto map and apply again) , the server access starts working but only less then 1 minute.. it's difficult to hone down it server issue when the server access stops working if i tried to do telnet on the server(port 443) it failed but if i reapply the VPN tunnel and telnet on Port 443 start working but less then 1 minute.

however more confusing is that telnet always work on this server for port it means it's not routing issue.

but on port 443 it works for less then i minute and after resetting the tunnel it starts working but for 1 minute only ...

any pointes to resolve this issue will be very helpful.

IOS Image : c2800nm-advipservicesk9-mz.124-3a.bin


Cisco Employee

Re: VPN tunnel cannot route one destination/ports more then a mi

Sounds like a packet size issue. Lower down the TCP MSS on the Lan interface of the router:

int fasteth0

ip tcp adjust-mss 1452


Lower down the value by 50 bytes each time, till you see any improvement.

*Please rate if helped.


Community Member

Re: VPN tunnel cannot route one destination/ports more then a mi

dear Kanishka,

i have reaaplied the ACl's and it start working fine , but i got another long pending issue resolved by your suggestion.


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