New Sophos Support Phone Numbers in Effect July 1st, 2023

This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

SNAT problem in Firmware 9.707.


Someone have problems with SNAT? SNAT ( Hide NAT ) from LAN to Internet.

After PPP interface is reconnected and received new / different IPv4 address, the UTMv9 is still using the old IPv4 address for old sessions ( verification using tcpdump ).

Sometimes it resolves by it self ... and sometimes after restart ...

It's sporadic and I was unable to understand why it's happening.

When there is a problem, new sessions are working and SNAT is using new IPv4.

In version 9.705-3 and before worked flawlessly with the same configuration.

Is there a way to clear NAT cache?

* Unable to open a case. I'm using free UTMv9 for personal testing purposes as VM ( although license specifies that I should be able to open a case ... but it seems that this option lost in Sophos on the way ... ).  

Thank You.

This thread was automatically locked due to age.
Parents Reply Children
  • Yep ... ppp0 interface should use new ISP IPv4 ... but it using old IPv4 ... or ... in rear occasions doesn't use SNAT and traffic goes out with private IP address.

    See tcpdump:

    ICMP to is using "old" IPv4 ... obviously has no ICMP Replies.

    Using new IPv4, is working and there are ICMP replies ( UTM changed it by itself ... no intervention from my part ).

    At the same time ppp0 interface and object "ISP Partner Fiber (Address) display correct IPv4 address:

    So ... it's definitely a BUG.