hello,
I have an issue with one of the client on POP3 access. My client having an MPLS link from a centrallized DC via GRE tunnel.
Client Switch -->Client ASA Firewall --> EDGE Router --> MPLS Cloud --> WAN G/W of DC --> CORE SWITCHES--> ASA1 --> ASA2 --> INET GW.
public IP 74.53.142.54 is hosted somewhere in US with ports 110,995 and 25. port 25 and 995 is accessible from all premises but when try to access 110 from client site, it is not responding. I am getting a flag "saA" in the client firewall and couldnt establish the connection.
port 995 was not working, but after mss adjusted to 1312 in the tunnel ends of Client and WAN G/W it satrted working.
Note: Internet is provided through the central DC and client doesnt have any direct internet access. no NAT in place on Client F/W. only access-list and routing.
if needed i can share the configuration. I am using a test PC with IP add 10.65.112.121 from the client premise and default route is pointing to the WAN G/W of Main DC through the F/W and EDGE Router.
Once the traffic reached WAN G/W it will be forwaded to Core Sw and then forwaded to ASA1 and ASA2 with IPS SSM-20 module.
natting is happening at the edge firewall as an interface PAT of the outside interface.
thanks in advance for any suggestions.
regards
Najeeb, Dubai