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hkusulja
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Posts: 75
Joined: Fri Apr 13, 2012 1:14 am

Bug with RouterOS 7 and lot TCP retransmissions using IPSec/GRE

Tue Mar 08, 2022 10:40 pm

Hello,
I have Mikrotik CCR1009 with RouterOS 6.49.4 running fine.
After upgrade to 7.1 (long term), or 7.1.3 (stable), or 7.2.rc4 (testing) i have issue with slow traffic, after downgrade to 6.49.4 it also working fine, so must be something about RouterOS 7 bug, not yet fixed.

Issue is that LAN client accessing internal web page application (over mikrotik gre+ipsec) to remote location via web browser like https://internalip , having JavaScript content >3 MB it is very very slow loading (several minutes).
On client I do see in wireshark lot of TCP retransmits.

Accessing public Internet web sites is working fine.
ICMP traffic, MTU also seems all fine and working.
Tried with or without FASTPATH ip firewall rule. Also tried allow all in ip firewall
Anyhow, traffic is working but very very slow only for remote site destination IP's for TCP connections

On Mikrotik device, this is going through GRE tunel with is first using IPSec ipsec policy
/interface gre add keepalive=5s,3 local-address=(LOCALWAN) name=toCentral remote-address=(REMOTELOCAL)
/ip ipsec profile add dh-group=modp2048 enc-algorithm=aes-256 name=central nat-traversal=no
/ip ipsec peer add address=(REMOTEWAN) exchange-mode=ike2 local-address=(LOCALWAN) name=toCentral
/ip ipsec proposal add enc-algorithms=aes-256-cbc name=proposal1 pfs-group=modp2048
/ip ipsec identity add peer=toCentral secret=XXXX
/ip ipsec policy dst-address=(REMOTELOCAL) peer=peer1 proposal=proposal1 protocol=gre src-address=(LOCALWAN) tunnel=yes
Any clue, how to debug or resolve?
 
sinofool
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Posts: 6
Joined: Wed Sep 08, 2021 10:19 pm

Re: Bug with RouterOS 7 and lot TCP retransmissions using IPSec/GRE

Sat Mar 12, 2022 2:53 am

I have a similar setup and disabled `keepalive` for the gre interface.
 
lfoerster
newbie
Posts: 36
Joined: Mon Mar 07, 2022 1:29 pm

Re: Bug with RouterOS 7 and lot TCP retransmissions using IPSec/GRE

Sat Mar 12, 2022 6:10 pm

Also Cisco recommends to NOT use keepalives in GRE tunnels:
https://www.cisco.com/c/en/us/support/d ... re-00.html
GRE btw. runs absolutely fine too between Cisco and Mikrotik:
https://administrator.de/contentid/398932
 
msutton
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Joined: Sun Mar 05, 2017 4:02 pm

Re: Bug with RouterOS 7 and lot TCP retransmissions using IPSec/GRE

Mon Mar 14, 2022 5:00 pm

I have had the same issue since upgrading to 7.1.
To troubleshoot I set the Auth and Encr Algorithms to NULL. This provided full speed again to my IPSEC/GRE endpoints.
After some trial and error I found that sha1 and aes-128 cbc are the highest I can go before it just turns to absolute trash.

This was not the case with version 6.

RB1100x4 connecting to multiple RB750Gr3.
 
hkusulja
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Posts: 75
Joined: Fri Apr 13, 2012 1:14 am

Re: Bug with RouterOS 7 and lot TCP retransmissions using IPSec/GRE

Mon Mar 21, 2022 7:10 pm

Hello,
Thank you for the tip and reference for keepalive, i tried to disable it, but still same behavior. Cisco config is not modified for years, since it was working for years on RoutersOS 6.x
After upgrade to RouterOS 7 , https traffic is very very slow and having a lot of TCP retransmissions. CPU is not utilized however.

So, the question is, what exactly is bug with RouterOS 7 stable that needs to be fixed. And how to troubleshoot further?
Mikrotik support email is not answering for weeks.
 
lyubomirtraykov
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Posts: 2
Joined: Tue Nov 05, 2019 1:37 pm

Re: Bug with RouterOS 7 and lot TCP retransmissions using IPSec/GRE

Tue Jun 07, 2022 12:39 pm

I just tried routeros 7.3 on RB750Gr3, and the bug is still not resolved. Did you find any workaround?

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