We have a 5555-x with multiple interfaces. Our Outside interface and DMZ interfaces have routable IP addresses and DMZ subnet is routed via IP address of the outside interface.

Stripped for readability.

interface GigabitEthernet0/0
 nameif outside
 security-level 0
 ip address

interface GigabitEthernet0/1
 nameif inside
 security-level 50
 ip address

interface GigabitEthernet0/2
 nameif dmz
 security-level 50
 ip address

object-group network newprod-hosts
 network-object host

route inside 1

I am trying to PAT port 22 to port 22

object network inside-ssh-host

nat (inside,dmz) static service tcp ssh ssh

access-list OUTSIDE extended permit tcp any host eq ssh

However, when I do that, and try to telnet to port 22 on I end up on a server that does not even belong to us and SSH version that I do not expect. Funny thing is, If i remove the ACL listed above, I can no longer access that port, so it is obvious that our ASA is doing something strange.....

% telnet 22
 Connected to www.<DOMAIN THAT DOES NOT BELONG TO US>.com.
 Escape character is '^]'.

Am I doing something wrong here, or do we need to contact our upstream provider to figure out what is happening there?

EDIT: We have recently acquired this DMZ subnet from the upstream provider, but ACL based routing of web traffic to our F5 sitting behind this ASA is working fine.

EDIT 2: When I do whois on this subnet (, it returns the information of the previous assignee, who had a larger subnet

  • Look at this question: networkengineering.stackexchange.com/questions/25174/…
    – Ron Maupin
    Dec 17 '15 at 0:48
  • Do a trace route to that address and post the results. @RonMaupin may be right and someone else is advertising it.
    – Ron Trunk
    Dec 17 '15 at 0:51
  • @RonTrunk @RonMauipn Thank you for replying. I figured out the "problem" and it was caused by complete and embarrassing brain malfunction on my end. What I was trying to do is impossible without PBR, because I was trying to NAT an IP address that did not belong to the ASA. It belonged to the downstream F5 device. And I was getting SSH prompt from the F5. Connected to was showing wrong domain because the ISP never delegated DNS control to us and the old assignee's DNS server was still resolving the PTR record.
    – solefald
    Dec 17 '15 at 2:03
  • Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you can provide your own answer and accept it.
    – Ron Maupin
    Aug 12 '17 at 23:37

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