Cisco ASA - Enabling SSH from any outside source to specific internal IP.

Hello,

I have been tasked with enabling SFTP from any outside source IP to a specific inside destination IP address.

I have entered the following static mapping and ACL, but it is still not working.  There is also a pre-existing object group defined with "port-object eq ssh" What am I missing here?

static (inside,outside) tcp xxx.xx.xxx.xxx ssh 10.1.1.81 ssh netmask 255.255.255.255 tcp 250 250

access-list inbound extended permit tcp host 0.0.0.0 host xxx.xx.xxx.xxx eq ssh
Kaiden_PAsked:
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Jimmy Larsson, CISSP, CEHNetwork and Security consultantCommented:
The outside source address will never ever be "host 0.0.0.0". Replace that with the keyword "any".

Best regards
Kvistofta
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DanJCommented:
check if the ACL does not have an entry that blocks your traffic.
the first ACL hist matters.
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Pro4iaCommented:
static (inside,outside) outsideip insideip netmask 255.255.255.255
access-list inbound extended permit tcp any host outsideip eq ssh
access-group inbound in interface outside
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Kaiden_PAuthor Commented:
I did exactly as instructed and replaced "host 0.0.0.0" with the keyword "any" and it is now working.  

Why did ASA accept command in the first place though?
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Jimmy Larsson, CISSP, CEHNetwork and Security consultantCommented:
The ASA accepts the command since it is proper syntax. "host 1.2.3.4" means "exactly 1.2.3.4" and can be done for any ip address. If you wanna allow ip packets whose source ip address is "0.0.0.0" you do "host 0.0.0.0" (and that kind of traffic actually exists, in theory. For example with dhcp requests).

But still "host 0.0.0.0" and "any" is not the same thing. Its not even close. ;)

Another way to say "any" in an access-list is to do something like "0.0.0.0 0.0.0.0" where the second row of 0:s is an netmask stating "whatever". Maybe you confuse this with "host 0.0.0.0" but the latter is actually equevalent to "0.0.0.0 255.255.255.255".

I am afraid I just confused you even more here. Sorry about that. :-)

/Kvistofta
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