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If I set new bookmarks when I'm at work, the changes don't propagate to my iOS devices (which are also with me at work) or to my iMac at home. But if I set new bookmarks at home, they do propagate to my other devices, at least most of the time. I've noticed that sometimes new bookmarks set on my iPhone 5 or iPad 3 don't always propagate to my iMac or to my MBA. But my question is, could my workplace's overzealous (security security!) IT have something in place that interferes with iCloud syncing?

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up vote 1 down vote accepted

From this Apple Support document detailing TCP and UDP ports used by Apple software, iCloud uses these ports:

25   - smtp    
80   - http    
443  - SSL (HTTPS)    
587  - Authenticated smtp    
993  - SSL IMAP    
5223 - DAV services

My guess is that it would be port 5223 which being blocked by your company.

As for your company's IT being 'overzealous', they are only doing exemplary due diligence protecting their network and server infrastructure, as well as any user (you) who connects, from nasties out there who would cause harm.

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Thank you for the response. I question the "due diligence" thing though because I work at a college I've been here since before we had Internet connectivity and before most of our IT guys ever played with a computer. I don't have these problems when I visit other institutions. – user33499 Feb 11 '13 at 21:55
"...I don't have these problems when I visit other institutions." Other institutions have either already opened these specific ports in their Internet-facing firewalls, which shows due diligence; or they have no port restrictions whatsoever, which shows a certain laxity in network security. This laxity may be deliberate on a public wireless network which needs to serve thousands; or the result of bad design if an internal wireless network. That's all. – IconDaemon Feb 12 '13 at 23:57
The delusion that outgoing port blocking provides any kind of security is just an annoyance for every single Internet user on the network. If any kind of packet on any port is allowed out to the Internet, it's equivalent to allowing all ports in the first place. Anything can be tunneled through that one open port. It serves no purpose but to block legitimate applications with unhelpful error messages because their HTTP connections succeed and other connections don't. – Locutus Nov 13 '13 at 9:15

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