About D Le Wando

D Le Wando · 08-20-2024

Hi,I'm getting dupplicate syn from our Firepower FTD. The setup is that VPN clients connect via outside (Internet) to access internal stuff. The VPN Clients get an IP from pool 10.1.1.x (for example) to access internal 10.2.2.x.Internet also needs to...

D Le Wando · 08-16-2024

Hi,if I try to enter module 1 via telnet, I get the error message: # connect module 1 telnet Type exit or Ctrl-] followed by . to quit. error reading input file # It's only possible to enter it with console: # connect module 1 console Telnet escap...

D Le Wando · 02-06-2024

Hi,pinging a VRF interface is not possible on FTD. Is this a feature?Pinging from VRF to somewhere works, but if you try to ping a VRF from outside, it's dropped by "implicit rule"? Phase: 5 Type: ACCESS-LIST Subtype: Result: DROP Elapsed time: 122 n...

D Le Wando · 08-29-2025

Have a similar one:Current Version:7.4.2.3-4Upgrade Version:7.6.0-113The upgrade failed to install.Database integrity check failed after schema update. The upgrade failed on Fri, Aug 29 at 7:30 UTC while running 600_schema/110_post_update_dbic.sh (Up...

D Le Wando · 08-26-2024

I picked 1 syslog message "%FTD-4-419002: Duplicate TCP SYN from int-outside:10.x.x.x/56521 to int-inside:10.y.y.y/443 with different initial sequence number"and checked outside + inside capture. Both captures show me that there's no duplicate packet...

D Le Wando · 08-26-2024

Thx for the capture hint. Now I see that NOT all packets are duplicated. I tried with my own client and see NO dup. So it seems that there's something special that causes dup packets ... I will troubleshoot this deeper...BTW, the NAT is done from tra...

D Le Wando · 08-23-2024

In real, there are 2 FTDs:Scenario 1 Internet access:Anyconnect Client - Internet - FTD1 (used for anyconnect) - FTD2 (used for firewalling) - Transp.Proxy - InternetSo the 2nd FTD also see the dup syn which were created by the 1st FTD:FTD2: Duplicat...

D Le Wando · 08-21-2024

Scenario 1 Internet access:Anyconnect Client - Internet - FTD - Transp.Proxy - Internet<<- how transp proxy connect to internet via FTD' i.e. the traffic retrun to FTD to access internet ?--> No. The Transp.Proxy has it's own Internet access

Member Since	‎08-15-2023 07:12 AM
Date Last Visited	‎10-13-2025 09:13 AM
Posts	13
Total Helpful Votes Received	4

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dupplicate tcp syn anyconnect

FTD 4000 series, connect module 1 telnet, error reading input file

Cisco FTD ping VRF

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Re: dupplicate tcp syn anyconnect

Re: dupplicate tcp syn anyconnect