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17.7 Legacy Series / Re: GRE over IPSec state issues
« on: October 13, 2017, 03:28:14 am »
Historically, I've had to do one of two things to resolve this, and have never had luck with sloppy state.
1) SEEMS OK: Set a floating rule, include the GRE interface, enable quick, target outbound only, set state to none and TCP flags to any, and use action pass. Traffic is controlled by knowing that only the router and any traffic it lets in to forward to send outbound on that interface.
2) BAD CLEARLY: Set a pair of stateless floating rules for each stateful rule I would normally configure, for example if my floating rule was to allow devices over the GRE tunnel in 192.168.0.0/24 to reach 192.168.99.10 over RDP (3389) locally, I would create the following two rules:
a) int lan,gre0 direction any src 192.168.0.0/24 srcport any dst 192.168.99.10 dstport 3389 flags=any state=none
b) int lan,gre0 direction any src 192.168.99.10 srcport 3389 dst 192.168.0.0/24 dstport any flags=any state=none
I'm open to better ideas. 2 is terrible as it allows any traffic from srcport 3389 on .99.10 to anything, obviously. 1 doesn't seem bad given if someone owns the firewall we're in trouble anyway.
1) SEEMS OK: Set a floating rule, include the GRE interface, enable quick, target outbound only, set state to none and TCP flags to any, and use action pass. Traffic is controlled by knowing that only the router and any traffic it lets in to forward to send outbound on that interface.
2) BAD CLEARLY: Set a pair of stateless floating rules for each stateful rule I would normally configure, for example if my floating rule was to allow devices over the GRE tunnel in 192.168.0.0/24 to reach 192.168.99.10 over RDP (3389) locally, I would create the following two rules:
a) int lan,gre0 direction any src 192.168.0.0/24 srcport any dst 192.168.99.10 dstport 3389 flags=any state=none
b) int lan,gre0 direction any src 192.168.99.10 srcport 3389 dst 192.168.0.0/24 dstport any flags=any state=none
I'm open to better ideas. 2 is terrible as it allows any traffic from srcport 3389 on .99.10 to anything, obviously. 1 doesn't seem bad given if someone owns the firewall we're in trouble anyway.