SMTP Overload?

[Guest]

[tyfeatherston]

We have several mailservers behind out endian firewall. In normal operation it works great. We have a problem when we try to send a mass email of about 1000 or so. Its almost like endian just blocks port 25 all then sudden and no one can get out on port 25 for a few hours. We know it is something with endian because when we remove it everything goes back to normal.

Any help would be appreciated.

Thanks!
Tyler