ScreenOS Firewalls (NOT SRX)
ScreenOS Firewalls (NOT SRX)

SSG5 Can't access Akamai hosted websites

‎07-29-2019 08:15 AM

We have several sites behind SSG5 firewalls that are unable to access Akamai-hosted websites all of the sudden. No changes on our end. The clients will either get a timeout loading the page, no response, or a random page load with missing objects. This affects anything that is hosted on Akamai. Bypassing the SSG5 resolves the issue. Anyone heard of anything similar or have any ideas to troubleshoot?


If we do an nslookup and see that the site resolves to an,, or alias...we know we'll have issues.


An example site ( - 

Non-authoritative answer:

ScreenOS Firewalls (NOT SRX)
Accepted by topic author jbeard7
‎07-29-2019 10:39 AM

Re: SSG5 Can't access Akamai hosted websites

‎07-29-2019 10:39 AM

We tracked this down to an MTU setting on the interface. Not sure why it suddenly started causing issues, but adjusting the MTU back to default (1500) and all of these sites start loading without issue.


The offending line:
set interface ethernet0/1 mtu 1492