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Can't access remote server via IPSec s2s after migration (xg135w to xgs136)

Hi,

We have an IPSec s2s connection, and there is a remote subnet 10.0.0.0/255.255.255.0.

Migration was done with configuration export/import and it seemed almost everything migrated successfully (only some firewall rules involvind ad users where missing).

On new device I can't ping or access remote AD server from xgs, which is crucial (AD controller).

  1. Old device (working):
    • ping 10.0.0.100 (remote server) from sophos ssh - OK
    • ping 10.0.0.110 (remote AD controller) from sophos ssh - OK
    • ping 10.0.0.110 (remote AD controller) from local PC - OK
    • packet capturing: packet is sent through ipsec0 interface from 10.0.1.1  (Port1 - LAN). No NAT or firewall rule applies.
  2. New device (not working):
    • ping 10.0.0.100 (remote server) from sophos ssh - OK
    • ping 10.0.0.110 (remote AD controller) from sophos ssh - FAILS
    • ping 10.0.0.110 (remote AD controller) from local PC - OK
    • packet capturing: packet is sent throuth ipsec0 interface but from 169.254.234.5 (ipsec0 interface). No NAT or firewall rule applies.

What may be causing the difference?



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  • Hi,

    the 169 indicates that the device does not have a valid IP address.

    Ian

    XG115W - v20.0.3 MR-3 - Home

    XG on VM 8 - v21 GA

    If a post solves your question please use the 'Verify Answer' button.

  • I thought the same, but couldn't figure out what can cause the difference after configuration migration, nor couldn't find a place where this can be configured:

  • All I can suggest is a restart to see if the address is correctly assigned.

    Ian

    XG115W - v20.0.3 MR-3 - Home

    XG on VM 8 - v21 GA

    If a post solves your question please use the 'Verify Answer' button.

  • Is there an alternative way to check the assigned address besides packet capturing?

  • Hi  

    What is the output of 'ip route show table 220'. In working case, this should be having src set to LAN ip of XGS

    You can check if there is any routing issue by looking at 'ip route get 10.0.0.110' 

  • Were there any explicit routes added via cish commands ? If so, then they also need to be exported explicitly on to the new device. Could you pls check ?

  •  

    Working device:

    > ip route show table 220
    10.0.0.0/24 dev ipsec0 scope link src 10.0.1.1
    > ip route get 10.0.0.110
    10.0.0.110 dev ipsec0 src 169.254.234.5 uid 0
    

    Non-working device:

    > ip route show table 220
    10.0.0.0/24 dev ipsec0 scope link src 10.0.2.1
    > ip route get 10.0.0.110
    10.0.0.110 dev ipsec0 src 169.254.234.5 uid 0

    Both 10.0.1.0/24 and 10.0.2.0/24 are local VLANs.

  • I don't think so, but could you specify how I check for such custom routes?

  • Did you change the local/remote subnets on both ends to reflect the change from 10.0.1.1 to 10.0.2.1 ?

    Mit freundlichem Gruß, best regards from Germany,

    Philipp Rusch

    New Vision GmbH, Germany
    Sophos Silver-Partner

    If a post solves your question please use the 'Verify Answer' button.

  • Generally, 'ip route get' and 'table 220' should be sowing same ip as source ip for a given destination, which is not the case in your setup.

    Since 'src 169.254.234.5' is shown both on XG and after moving on to XGS, you might not have any LAN interface configured with an ip that is part of 'local subnet' used for s2s ipsec tunnel. In such case, on your XG you would be having below 2 cish clis configured via cish (one is for route and the other one for snat) that helps XG generated traffic reaching AD server via the tunnel. Pls. check and ensure the clis are added on your new XGS.

    system ipsec_route add host <Ad server ip>  tunnelname <IPsec s2s tunnel name>

    set advanced-firewall sys-traffic-nat add destination <Ad server ip> snatip <some ip address of 'local subnet' used in the ipsec tunnel.

    On the other hand, if we add a LAN port on XGS with an ip that is part of the 'local subnet' of ipsec tunnel, ipsec tunnel bringup will take care of updating table 220 with the ip configured on the LAN port as source ip.