Issues with ASA 5510 not staying connected on new ATT Line

[adamhoud]

Have had an ASA 5510 running for over a year, routing out to a 2821 with 4 T1 lines connected. I am trying to switch this over to a new ATT managed ethernet 20Mb connection.

The setup isn't terribly complicated, all I am really doing is changing the default route to int 0/3 with the appropriate IP information assigned, and changing the NAT from int 0/0 to 0/3. Also reconfiguring the VPN tunnels to the data center.

Everything comes up fine and posts full 20Mb bandwidth, but consistently after about 1.5 hours the connection drops. Reloading the firewall brings the connection back up...I am at my whits end trying to figure out the cause of dropping connection.


PS. line is tested fine for hours on a laptop with static IP going straight through the managed ethernet.

 

[DreamerBrian]

What type of errors are you getting on the involved interfaces?

 

[G33K454URU5 R3X]

Similar thread from Cisco, where another appliance was interfering:

https://supportforums.cisco.com/thread/2043090

 

[dark_15]

Are the interface error counters on int0/3 incrementing? I've seen this before where there's a speed/duplex mismatch on the interface. You should be able to call AT&T and have them confirm speed/duplex on their side as well. Other issues could be MTU size is messed up or Path MTU Discovery is disabled.